diff --git a/.mcp.json b/.mcp.json
new file mode 100644
index 0000000..e69de29
diff --git a/src/lib/components/navigation/footer.svelte b/src/lib/components/navigation/footer.svelte
index 8fb2e54..4afa526 100644
--- a/src/lib/components/navigation/footer.svelte
+++ b/src/lib/components/navigation/footer.svelte
@@ -23,6 +23,7 @@
 		{ href: resolve('/weather/week'), label: '7-Day Forecast' },
 		{ href: resolve('/weather/compare'), label: 'Model Comparison' },
 		{ href: resolve('/weather/14-day'), label: '14-Day Forecast' },
+		{ href: resolve('/weather/seasonal'), label: 'Seasonal Outlook' },
 		{ href: resolve('/weather/historical'), label: 'Historical Weather' },
 		{ href: resolve('/weather/maps'), label: 'Weather Maps' }
 	];
diff --git a/src/lib/components/navigation/header.svelte b/src/lib/components/navigation/header.svelte
index 85ec8dc..3fd1ef1 100644
--- a/src/lib/components/navigation/header.svelte
+++ b/src/lib/components/navigation/header.svelte
@@ -12,7 +12,10 @@
 	import LocationSearch from '$lib/components/location/location-search.svelte';
 	import UnitSelector from '$lib/components/unit-selector.svelte';
 
-	import PremiumBadge from '$lib/paywall/PremiumBadge.svelte';
+	import SupporterBadge from '$lib/paywall/SupporterBadge.svelte';
+
+	import SettingsMenu from './settings-menu.svelte';
+	import ThemeIcon from './theme-icon.svelte';
 
 	interface Props {
 		onMenuToggle?: () => void;
@@ -60,6 +63,8 @@
 			goto(resolve('/weather/14-day/[location]', { location: locationRoute }));
 		} else if (currentPath.startsWith('/weather/historical')) {
 			goto(resolve('/weather/historical/[location]', { location: locationRoute }));
+		} else if (currentPath.startsWith('/weather/seasonal')) {
+			goto(resolve('/weather/seasonal/[location]', { location: locationRoute }));
 		} else {
 			goto(resolve('/weather/week/[location]', { location: locationRoute }));
 		}
@@ -117,63 +122,31 @@
 		/>
 	</div>
 
-	<!-- Measurement units -->
-	<UnitSelector />
+	<!-- Phones only have room for one control, so units, theme and supporter
+	     status collapse into a single settings menu below md. -->
+	<div class="md:hidden">
+		<SettingsMenu />
+	</div>
 
-	<!-- Premium status / unlock -->
-	<PremiumBadge />
+	<!-- md+: the same settings as individual controls. Kept mounted (not `{#if}`)
+	     so SupporterBadge still verifies the key on every viewport. -->
+	<div class="hidden items-center gap-3 md:flex">
+		<!-- Measurement units -->
+		<UnitSelector />
 
-	<!-- Theme toggle: system → light → dark -->
-	<button
-		class="flex h-9 w-9 shrink-0 cursor-pointer items-center justify-center rounded-full border border-border/70 text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
-		onclick={cycleTheme}
-		title={themeTitles[$storedTheme]}
-		aria-label={themeTitles[$storedTheme]}
-	>
-		{#if $storedTheme === 'light'}
-			<!-- sun -->
-			<svg
-				class="h-4.5 w-4.5"
-				fill="none"
-				stroke="currentColor"
-				viewBox="0 0 24 24"
-				stroke-width="1.75"
-			>
-				<circle cx="12" cy="12" r="4" />
-				<path
-					stroke-linecap="round"
-					d="M12 2v2m0 16v2M4.93 4.93l1.41 1.41m11.32 11.32 1.41 1.41M2 12h2m16 0h2M4.93 19.07l1.41-1.41m11.32-11.32 1.41-1.41"
-				/>
-			</svg>
-		{:else if $storedTheme === 'dark'}
-			<!-- moon -->
-			<svg
-				class="h-4.5 w-4.5"
-				fill="none"
-				stroke="currentColor"
-				viewBox="0 0 24 24"
-				stroke-width="1.75"
-			>
-				<path
-					stroke-linecap="round"
-					stroke-linejoin="round"
-					d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8Z"
-				/>
-			</svg>
-		{:else}
-			<!-- monitor (system) -->
-			<svg
-				class="h-4.5 w-4.5"
-				fill="none"
-				stroke="currentColor"
-				viewBox="0 0 24 24"
-				stroke-width="1.75"
-			>
-				<rect x="3" y="4" width="18" height="13" rx="2" />
-				<path stroke-linecap="round" d="M8 21h8m-4-4v4" />
-			</svg>
-		{/if}
-	</button>
+		<!-- Supporter status / unlock -->
+		<SupporterBadge />
+
+		<!-- Theme toggle: system → light → dark -->
+		<button
+			class="flex h-9 w-9 shrink-0 cursor-pointer items-center justify-center rounded-full border border-border/70 text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
+			onclick={cycleTheme}
+			title={themeTitles[$storedTheme]}
+			aria-label={themeTitles[$storedTheme]}
+		>
+			<ThemeIcon theme={$storedTheme} />
+		</button>
+	</div>
 </header>
 
 <style>
diff --git a/src/lib/components/navigation/settings-menu.svelte b/src/lib/components/navigation/settings-menu.svelte
new file mode 100644
index 0000000..b85cbfa
--- /dev/null
+++ b/src/lib/components/navigation/settings-menu.svelte
@@ -0,0 +1,123 @@
+<script lang="ts">
+	import { type Theme, storedTheme } from '$lib/stores/settings';
+
+	import * as Popover from '$lib/components/ui/popover';
+	import UnitOptions from '$lib/components/unit-options.svelte';
+
+	import UnlockDialog from '$lib/paywall/UnlockDialog.svelte';
+	import { isSupporter } from '$lib/paywall/supporter';
+
+	import ThemeIcon from './theme-icon.svelte';
+
+	// The topbar has room for one control on a phone, so units, theme and the
+	// supporter status share this menu instead of each carrying its own trigger.
+	const THEMES: { value: Theme; label: string }[] = [
+		{ value: 'system', label: 'System' },
+		{ value: 'light', label: 'Light' },
+		{ value: 'dark', label: 'Dark' }
+	];
+
+	let open = $state(false);
+	let unlockOpen = $state(false);
+</script>
+
+<Popover.Root bind:open>
+	<Popover.Trigger
+		class="flex h-9 w-9 shrink-0 cursor-pointer items-center justify-center rounded-full border border-border/70 text-muted-foreground transition-colors hover:bg-muted hover:text-foreground data-[state=open]:bg-muted data-[state=open]:text-foreground"
+		aria-label="Settings"
+		title="Settings"
+	>
+		<!-- gear -->
+		<svg
+			class="h-4.5 w-4.5"
+			fill="none"
+			stroke="currentColor"
+			viewBox="0 0 24 24"
+			stroke-width="1.75"
+		>
+			<circle cx="12" cy="12" r="3" />
+			<path
+				stroke-linecap="round"
+				stroke-linejoin="round"
+				d="M19.4 15a1.7 1.7 0 0 0 .3 1.9l.1.1a2 2 0 1 1-2.8 2.8l-.1-.1a1.7 1.7 0 0 0-2.9 1.2v.2a2 2 0 1 1-4 0v-.1a1.7 1.7 0 0 0-1.1-1.5 1.7 1.7 0 0 0-1.9.3l-.1.1a2 2 0 1 1-2.8-2.8l.1-.1a1.7 1.7 0 0 0-1.2-2.9H3a2 2 0 1 1 0-4h.1a1.7 1.7 0 0 0 1.5-1.1 1.7 1.7 0 0 0-.3-1.9l-.1-.1a2 2 0 1 1 2.8-2.8l.1.1a1.7 1.7 0 0 0 1.9.3H9a1.7 1.7 0 0 0 1-1.5V3a2 2 0 1 1 4 0v.1a1.7 1.7 0 0 0 2.9 1.2l.1-.1a2 2 0 1 1 2.8 2.8l-.1.1a1.7 1.7 0 0 0-.3 1.9V9a1.7 1.7 0 0 0 1.5 1H21a2 2 0 1 1 0 4h-.1a1.7 1.7 0 0 0-1.5 1Z"
+			/>
+		</svg>
+	</Popover.Trigger>
+
+	<Popover.Content align="end" class="w-72 border-border">
+		<div class="flex flex-col gap-4">
+			<UnitOptions />
+
+			<div>
+				<span
+					class="mb-1.5 block text-[11px] font-semibold tracking-wide text-muted-foreground uppercase"
+				>
+					Theme
+				</span>
+				<div class="flex gap-1 rounded-lg bg-muted p-0.5">
+					{#each THEMES as option (option.value)}
+						{@const active = $storedTheme === option.value}
+						<button
+							class="flex flex-1 cursor-pointer items-center justify-center gap-1.5 rounded-md px-2 py-1.5 text-[13px] font-semibold transition-colors {active
+								? 'bg-background text-foreground shadow-sm'
+								: 'text-muted-foreground hover:text-foreground'}"
+							aria-pressed={active}
+							onclick={() => storedTheme.set(option.value)}
+						>
+							<ThemeIcon theme={option.value} class="h-4 w-4" />
+							{option.label}
+						</button>
+					{/each}
+				</div>
+			</div>
+
+			<div class="border-t border-border/70 pt-3">
+				<button
+					type="button"
+					class="flex w-full cursor-pointer items-center gap-2.5 rounded-lg px-2 py-2 text-left transition-colors hover:bg-muted"
+					onclick={() => {
+						open = false;
+						unlockOpen = true;
+					}}
+				>
+					{#if $isSupporter}
+						<!-- star -->
+						<svg
+							class="h-4.5 w-4.5 shrink-0 text-amber-500"
+							viewBox="0 0 24 24"
+							fill="currentColor"
+							aria-hidden="true"
+						>
+							<path
+								d="M12 2.5l2.9 6 6.6.9-4.8 4.6 1.2 6.5L12 17.9 6.1 20.5l1.2-6.5L2.5 9.4l6.6-.9L12 2.5z"
+							/>
+						</svg>
+					{:else}
+						<!-- padlock -->
+						<svg
+							class="h-4.5 w-4.5 shrink-0 text-muted-foreground"
+							fill="none"
+							stroke="currentColor"
+							viewBox="0 0 24 24"
+							stroke-width="1.75"
+							aria-hidden="true"
+						>
+							<rect x="4" y="10" width="16" height="11" rx="2" />
+							<path stroke-linecap="round" d="M8 10V7a4 4 0 0 1 8 0v3" />
+						</svg>
+					{/if}
+					<span class="min-w-0 flex-1">
+						<span class="block text-[13px] font-semibold">
+							{$isSupporter ? 'Supporter extras active' : 'Support Drizz.li'}
+						</span>
+						<span class="block text-[11px] text-muted-foreground">
+							{$isSupporter ? 'Manage your access key' : 'Unlock the supporter extras'}
+						</span>
+					</span>
+				</button>
+			</div>
+		</div>
+	</Popover.Content>
+</Popover.Root>
+
+<UnlockDialog bind:open={unlockOpen} />
diff --git a/src/lib/components/navigation/theme-icon.svelte b/src/lib/components/navigation/theme-icon.svelte
new file mode 100644
index 0000000..9664407
--- /dev/null
+++ b/src/lib/components/navigation/theme-icon.svelte
@@ -0,0 +1,36 @@
+<script lang="ts">
+	import type { Theme } from '$lib/stores/settings';
+
+	interface Props {
+		theme: Theme;
+		class?: string;
+	}
+
+	let { theme, class: className = 'h-4.5 w-4.5' }: Props = $props();
+</script>
+
+{#if theme === 'light'}
+	<!-- sun -->
+	<svg class={className} fill="none" stroke="currentColor" viewBox="0 0 24 24" stroke-width="1.75">
+		<circle cx="12" cy="12" r="4" />
+		<path
+			stroke-linecap="round"
+			d="M12 2v2m0 16v2M4.93 4.93l1.41 1.41m11.32 11.32 1.41 1.41M2 12h2m16 0h2M4.93 19.07l1.41-1.41m11.32-11.32 1.41-1.41"
+		/>
+	</svg>
+{:else if theme === 'dark'}
+	<!-- moon -->
+	<svg class={className} fill="none" stroke="currentColor" viewBox="0 0 24 24" stroke-width="1.75">
+		<path
+			stroke-linecap="round"
+			stroke-linejoin="round"
+			d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8Z"
+		/>
+	</svg>
+{:else}
+	<!-- monitor (system) -->
+	<svg class={className} fill="none" stroke="currentColor" viewBox="0 0 24 24" stroke-width="1.75">
+		<rect x="3" y="4" width="18" height="13" rx="2" />
+		<path stroke-linecap="round" d="M8 21h8m-4-4v4" />
+	</svg>
+{/if}
diff --git a/src/lib/components/navigation/weather-nav.svelte b/src/lib/components/navigation/weather-nav.svelte
index 4647d05..720faf9 100644
--- a/src/lib/components/navigation/weather-nav.svelte
+++ b/src/lib/components/navigation/weather-nav.svelte
@@ -30,6 +30,12 @@
 				'M3 15a4 4 0 004 4h9a5 5 0 10-.1-9.999 5.002 5.002 0 10-9.78 2.096A4.001 4.001 0 003 15z'
 			]
 		},
+		{
+			title: 'Seasonal',
+			url: '/weather/seasonal' as const,
+			// rising trend line (long-range outlook)
+			iconPaths: ['M3 17l6-6 4 4 7-7', 'M16 8h5v5']
+		},
 		{
 			title: 'Historical',
 			url: '/weather/historical' as const,
diff --git a/src/lib/components/unit-options.svelte b/src/lib/components/unit-options.svelte
new file mode 100644
index 0000000..a798afe
--- /dev/null
+++ b/src/lib/components/unit-options.svelte
@@ -0,0 +1,67 @@
+<script lang="ts">
+	import { type UnitPrefs, storedUnits } from '$lib/stores/settings';
+
+	// each group maps a stored unit key to its selectable options
+	const UNIT_GROUPS: {
+		key: keyof UnitPrefs;
+		label: string;
+		options: { value: string; label: string }[];
+	}[] = [
+		{
+			key: 'temperature_unit',
+			label: 'Temperature',
+			options: [
+				{ value: 'celsius', label: '°C' },
+				{ value: 'fahrenheit', label: '°F' }
+			]
+		},
+		{
+			key: 'wind_speed_unit',
+			label: 'Wind speed',
+			options: [
+				{ value: 'kmh', label: 'km/h' },
+				{ value: 'ms', label: 'm/s' },
+				{ value: 'mph', label: 'mph' },
+				{ value: 'kn', label: 'kn' }
+			]
+		},
+		{
+			key: 'precipitation_unit',
+			label: 'Precipitation',
+			options: [
+				{ value: 'mm', label: 'mm' },
+				{ value: 'inch', label: 'inch' }
+			]
+		}
+	];
+
+	function setUnit(key: keyof UnitPrefs, value: string) {
+		storedUnits.update((u) => ({ ...u, [key]: value }));
+	}
+</script>
+
+<div class="flex flex-col gap-4">
+	{#each UNIT_GROUPS as group (group.key)}
+		<div>
+			<span
+				class="mb-1.5 block text-[11px] font-semibold tracking-wide text-muted-foreground uppercase"
+			>
+				{group.label}
+			</span>
+			<div class="flex gap-1 rounded-lg bg-muted p-0.5">
+				{#each group.options as opt (opt.value)}
+					{@const active = $storedUnits[group.key] === opt.value}
+					<button
+						class="flex-1 cursor-pointer rounded-md px-2 py-1.5 text-[13px] font-semibold transition-colors {active
+							? 'bg-background text-foreground shadow-sm'
+							: 'text-muted-foreground hover:text-foreground'}"
+						aria-pressed={active}
+						onclick={() => setUnit(group.key, opt.value)}
+					>
+						{opt.label}
+					</button>
+				{/each}
+			</div>
+		</div>
+	{/each}
+</div>
diff --git a/src/lib/components/unit-selector.svelte b/src/lib/components/unit-selector.svelte
index b123eb1..a0bc34f 100644
--- a/src/lib/components/unit-selector.svelte
+++ b/src/lib/components/unit-selector.svelte
@@ -1,45 +1,6 @@
 <script lang="ts">
-	import { type UnitPrefs, storedUnits } from '$lib/stores/settings';
-
 	import * as Popover from '$lib/components/ui/popover';
-
-	// each group maps a stored unit key to its selectable options
-	const UNIT_GROUPS: {
-		key: keyof UnitPrefs;
-		label: string;
-		options: { value: string; label: string }[];
-	}[] = [
-		{
-			key: 'temperature_unit',
-			label: 'Temperature',
-			options: [
-				{ value: 'celsius', label: '°C' },
-				{ value: 'fahrenheit', label: '°F' }
-			]
-		},
-		{
-			key: 'wind_speed_unit',
-			label: 'Wind speed',
-			options: [
-				{ value: 'kmh', label: 'km/h' },
-				{ value: 'ms', label: 'm/s' },
-				{ value: 'mph', label: 'mph' },
-				{ value: 'kn', label: 'kn' }
-			]
-		},
-		{
-			key: 'precipitation_unit',
-			label: 'Precipitation',
-			options: [
-				{ value: 'mm', label: 'mm' },
-				{ value: 'inch', label: 'inch' }
-			]
-		}
-	];
-
-	function setUnit(key: keyof UnitPrefs, value: string) {
-		storedUnits.update((u) => ({ ...u, [key]: value }));
-	}
+	import UnitOptions from '$lib/components/unit-options.svelte';
 </script>
 
 <Popover.Root>
@@ -65,30 +26,6 @@
 		</svg>
 	</Popover.Trigger>
 	<Popover.Content align="end" class="w-64 border-border">
-		<div class="flex flex-col gap-4">
-			{#each UNIT_GROUPS as group (group.key)}
-				<div>
-					<span
-						class="mb-1.5 block text-[11px] font-semibold tracking-wide text-muted-foreground uppercase"
-					>
-						{group.label}
-					</span>
-					<div class="flex gap-1 rounded-lg bg-muted p-0.5">
-						{#each group.options as opt (opt.value)}
-							{@const active = $storedUnits[group.key] === opt.value}
-							<button
-								class="flex-1 cursor-pointer rounded-md px-2 py-1.5 text-[13px] font-semibold transition-colors {active
-									? 'bg-background text-foreground shadow-sm'
-									: 'text-muted-foreground hover:text-foreground'}"
-								aria-pressed={active}
-								onclick={() => setUnit(group.key, opt.value)}
-							>
-								{opt.label}
-							</button>
-						{/each}
-					</div>
-				</div>
-			{/each}
-		</div>
+		<UnitOptions />
 	</Popover.Content>
 </Popover.Root>
diff --git a/src/lib/paywall/PaywallGate.svelte b/src/lib/paywall/PaywallGate.svelte
index 7641c11..397aae8 100644
--- a/src/lib/paywall/PaywallGate.svelte
+++ b/src/lib/paywall/PaywallGate.svelte
@@ -2,8 +2,8 @@
 	import { onMount } from 'svelte';
 
 	import UnlockDialog from './UnlockDialog.svelte';
-	import { PREMIUM_PERKS, SIGNUP_URL, getPremiumPrice } from './config';
-	import { isPremium, premiumState, refreshPremium } from './premium';
+	import { SUPPORTER_PERKS, SIGNUP_URL, getSupporterPrice } from './config';
+	import { isSupporter, supporterState, refreshSupporter } from './supporter';
 
 	interface Props {
 		/** Short feature name shown in the locked panel headline. */
@@ -14,16 +14,16 @@
 	let { feature = 'This page', children }: Props = $props();
 
 	let unlockOpen = $state(false);
-	const price = getPremiumPrice();
+	const price = getSupporterPrice();
 
 	// Re-verify the stored key whenever the gate mounts.
-	onMount(refreshPremium);
+	onMount(refreshSupporter);
 
 	// Show a brief spinner only when we have no cached answer yet and are checking.
-	let initialChecking = $derived($premiumState.status === 'checking' && !$isPremium);
+	let initialChecking = $derived($supporterState.status === 'checking' && !$isSupporter);
 </script>
 
-{#if $isPremium}
+{#if $isSupporter}
 	{@render children()}
 {:else if initialChecking}
 	<div class="flex items-center justify-center py-24 text-sm text-muted-foreground">
@@ -59,7 +59,7 @@
 		</p>
 
 		<ul class="mx-auto mt-5 grid max-w-sm gap-2 text-left">
-			{#each PREMIUM_PERKS as perk (perk)}
+			{#each SUPPORTER_PERKS as perk (perk)}
 				<li class="flex items-start gap-2.5 text-sm">
 					<svg
 						class="mt-0.5 h-4 w-4 shrink-0 text-primary"
@@ -93,7 +93,7 @@
 			</button>
 		</div>
 
-		{#if $premiumState.status === 'invalid'}
+		{#if $supporterState.status === 'invalid'}
 			<p class="mt-4 text-xs text-amber-600 dark:text-amber-400">
 				Your saved key is no longer valid or has expired.
 			</p>
diff --git a/src/lib/paywall/PremiumBadge.svelte b/src/lib/paywall/SupporterBadge.svelte
similarity index 75%
rename from src/lib/paywall/PremiumBadge.svelte
rename to src/lib/paywall/SupporterBadge.svelte
index e47a5d5..1662401 100644
--- a/src/lib/paywall/PremiumBadge.svelte
+++ b/src/lib/paywall/SupporterBadge.svelte
@@ -2,31 +2,31 @@
 	import { onMount } from 'svelte';
 
 	import UnlockDialog from './UnlockDialog.svelte';
-	import { isPremium, refreshPremium } from './premium';
+	import { isSupporter, refreshSupporter } from './supporter';
 
 	let open = $state(false);
 
 	// Verify once on load so the badge reflects real status site-wide.
-	onMount(refreshPremium);
+	onMount(refreshSupporter);
 </script>
 
 <button
 	type="button"
-	class="flex h-9 shrink-0 cursor-pointer items-center gap-1.5 rounded-full border px-3 text-xs font-semibold transition-colors {$isPremium
+	class="flex h-9 shrink-0 cursor-pointer items-center gap-1.5 rounded-full border px-3 text-xs font-semibold transition-colors {$isSupporter
 		? 'border-amber-400/50 bg-amber-400/10 text-amber-700 hover:bg-amber-400/20 dark:text-amber-300'
 		: 'border-border/70 text-muted-foreground hover:bg-muted hover:text-foreground'}"
 	onclick={() => (open = true)}
-	title={$isPremium ? 'Supporter extras active' : 'Support Drizz.li'}
-	aria-label={$isPremium ? 'Supporter extras active' : 'Support Drizz.li'}
+	title={$isSupporter ? 'Supporter extras active' : 'Support Drizz.li'}
+	aria-label={$isSupporter ? 'Supporter extras active' : 'Support Drizz.li'}
 >
-	{#if $isPremium}
+	{#if $isSupporter}
 		<!-- star -->
 		<svg class="h-4 w-4" viewBox="0 0 24 24" fill="currentColor" aria-hidden="true">
 			<path
 				d="M12 2.5l2.9 6 6.6.9-4.8 4.6 1.2 6.5L12 17.9 6.1 20.5l1.2-6.5L2.5 9.4l6.6-.9L12 2.5z"
 			/>
 		</svg>
-		<span class="hidden sm:inline">Premium</span>
+		<span class="hidden sm:inline">Supporter</span>
 	{:else}
 		<!-- padlock -->
 		<svg
@@ -40,7 +40,7 @@
 			<rect x="4" y="10" width="16" height="11" rx="2" />
 			<path stroke-linecap="round" d="M8 10V7a4 4 0 0 1 8 0v3" />
 		</svg>
-		<span class="hidden sm:inline">Premium</span>
+		<span class="hidden sm:inline">Supporter</span>
 	{/if}
 </button>
 
diff --git a/src/lib/paywall/UnlockDialog.svelte b/src/lib/paywall/UnlockDialog.svelte
index 64a0658..3c4f854 100644
--- a/src/lib/paywall/UnlockDialog.svelte
+++ b/src/lib/paywall/UnlockDialog.svelte
@@ -6,8 +6,8 @@
 	import { Input } from '$lib/components/ui/input';
 	import { Label } from '$lib/components/ui/label';
 
-	import { SIGNUP_URL, getPremiumPrice } from './config';
-	import { clearLicense, isPremium, premiumState, storedLicenseKey, verifyKey } from './premium';
+	import { SIGNUP_URL, getSupporterPrice } from './config';
+	import { clearLicense, isSupporter, supporterState, storedLicenseKey, verifyKey } from './supporter';
 
 	interface Props {
 		open?: boolean;
@@ -15,7 +15,7 @@
 
 	let { open = $bindable(false) }: Props = $props();
 
-	const price = getPremiumPrice();
+	const price = getSupporterPrice();
 
 	// Prefill with the stored key so an existing subscriber sees their key.
 	let keyInput = $state('');
@@ -50,8 +50,8 @@
 	}
 
 	let expiresLabel = $derived.by(() => {
-		const exp = $premiumState.expires;
-		if ($premiumState.status !== 'valid') return null;
+		const exp = $supporterState.expires;
+		if ($supporterState.status !== 'valid') return null;
 		if (!exp) return 'Lifetime access';
 		return `Active until ${formatZoned(new Date(exp), 'UTC', 'd LLL yyyy')}`;
 	});
@@ -66,7 +66,7 @@
 			</Dialog.Description>
 		</Dialog.Header>
 
-		{#if $isPremium && $premiumState.status === 'valid'}
+		{#if $isSupporter && $supporterState.status === 'valid'}
 			<div
 				class="flex items-start gap-3 rounded-lg border border-emerald-300/60 bg-emerald-50 px-3.5 py-3 text-sm text-emerald-800 dark:border-emerald-800/50 dark:bg-emerald-950/30 dark:text-emerald-200"
 			>
@@ -81,7 +81,7 @@
 					<circle cx="12" cy="12" r="9" />
 				</svg>
 				<div>
-					<p class="font-semibold">Premium is active</p>
+					<p class="font-semibold">Supporter extras are active</p>
 					{#if expiresLabel}<p class="text-xs opacity-80">{expiresLabel}</p>{/if}
 				</div>
 			</div>
@@ -102,7 +102,7 @@
 
 			{#if localError}
 				<p class="text-sm text-destructive">{localError}</p>
-			{:else if $premiumState.status === 'error'}
+			{:else if $supporterState.status === 'error'}
 				<p class="text-sm text-destructive">
 					Couldn't reach the server. Check your connection and try again.
 				</p>
@@ -114,7 +114,7 @@
 		</form>
 
 		<Dialog.Footer class="flex-col items-stretch gap-2 sm:flex-col sm:items-stretch">
-			{#if $isPremium}
+			{#if $isSupporter}
 				<button
 					type="button"
 					class="cursor-pointer text-center text-xs text-muted-foreground underline-offset-2 hover:text-foreground hover:underline"
diff --git a/src/lib/paywall/config.ts b/src/lib/paywall/config.ts
index 34610c8..338fe8d 100644
--- a/src/lib/paywall/config.ts
+++ b/src/lib/paywall/config.ts
@@ -28,9 +28,9 @@ const CURRENCY_SYMBOL: Record<string, string> = { EUR: '€', USD: '$', CHF: 'CH
 const US_ZONES =
 	/^America\/(New_York|Detroit|Chicago|Denver|Boise|Phoenix|Los_Angeles|Anchorage|Adak|Juneau|Sitka|Nome|Yakutat|Menominee|Indiana|Kentucky|North_Dakota)/;
 
-export type PremiumCurrency = 'EUR' | 'USD' | 'CHF';
+export type SupporterCurrency = 'EUR' | 'USD' | 'CHF';
 
-export function detectCurrency(): PremiumCurrency {
+export function detectCurrency(): SupporterCurrency {
 	if (typeof Intl === 'undefined') return 'EUR';
 	let tz = '';
 	try {
@@ -53,15 +53,19 @@ export function detectCurrency(): PremiumCurrency {
 }
 
 /** Display price for the paywall panel, e.g. "€3 / month" or "CHF 3 / month". */
-export function getPremiumPrice(): string {
-	if (env.VITE_PREMIUM_PRICE) return env.VITE_PREMIUM_PRICE;
+export function getSupporterPrice(): string {
+	// VITE_PREMIUM_PRICE is the pre-rename name, still honoured so an existing
+	// deployment's .env keeps working.
+	const configured = env.VITE_SUPPORTER_PRICE ?? env.VITE_PREMIUM_PRICE;
+	if (configured) return configured;
 	const currency = detectCurrency();
 	const symbol = CURRENCY_SYMBOL[currency];
 	return currency === 'CHF' ? `${symbol} 3 / month` : `${symbol}3 / month`;
 }
 
 /** Short, human list of what supporting unlocks (shown on the locked panel). */
-export const PREMIUM_PERKS = [
+export const SUPPORTER_PERKS = [
 	'Historical weather & climate-normal comparisons',
+	'Seasonal outlook: months ahead vs the climate normal',
 	'New supporter extras as they land'
 ];
diff --git a/src/lib/paywall/premium.ts b/src/lib/paywall/supporter.ts
similarity index 59%
rename from src/lib/paywall/premium.ts
rename to src/lib/paywall/supporter.ts
index 91f212a..710ddfa 100644
--- a/src/lib/paywall/premium.ts
+++ b/src/lib/paywall/supporter.ts
@@ -1,5 +1,5 @@
 /**
- * Premium (subscription) state.
+ * Supporter (subscription) state.
  *
  * The user pastes an access key once; it is stored locally and re-verified
  * against the self-hosted verify API on load. The last good result is cached so
@@ -16,10 +16,10 @@ import { persisted } from 'svelte-persisted-store';
 
 import { PAYWALL_API_BASE } from './config';
 
-/** The subscriber's access key, e.g. "DRZ-7Q2K-9F4M-XW3P". Empty when signed out. */
+/** The supporter's access key, e.g. "DRZ-7Q2K-9F4M-XW3P". Empty when signed out. */
 export const storedLicenseKey = persisted<string>('license_key', '');
 
-export interface PremiumCache {
+export interface SupporterCache {
 	valid: boolean;
 	tier?: string;
 	/** ISO date the subscription lapses, or null for a lifetime key. */
@@ -28,20 +28,40 @@ export interface PremiumCache {
 	checkedAt: number;
 }
 
+const CACHE_KEY = 'supporter_cache_v1';
+const LEGACY_CACHE_KEY = 'premium_cache_v1';
+
+/**
+ * Carries the pre-rename cache over on first load, so supporters who already
+ * verified aren't shown a locked page while the key re-verifies.
+ */
+function readLegacyCache(): SupporterCache | null {
+	if (typeof localStorage === 'undefined') return null;
+	try {
+		if (localStorage.getItem(CACHE_KEY)) return null;
+		const legacy = localStorage.getItem(LEGACY_CACHE_KEY);
+		if (!legacy) return null;
+		localStorage.removeItem(LEGACY_CACHE_KEY);
+		return JSON.parse(legacy) as SupporterCache;
+	} catch {
+		return null;
+	}
+}
+
 /** Last verify result, persisted so the UI doesn't flash "locked" on reload. */
-export const storedPremiumCache = persisted<PremiumCache | null>('premium_cache_v1', null);
+export const storedSupporterCache = persisted<SupporterCache | null>(CACHE_KEY, readLegacyCache());
 
-export type PremiumStatus = 'idle' | 'checking' | 'valid' | 'invalid' | 'error';
+export type SupporterStatus = 'idle' | 'checking' | 'valid' | 'invalid' | 'error';
 
-export interface PremiumState {
-	status: PremiumStatus;
+export interface SupporterState {
+	status: SupporterStatus;
 	tier?: string;
 	expires?: string | null;
 	error?: string;
 }
 
 /** Live verification state for the current session. */
-export const premiumState = writable<PremiumState>({ status: 'idle' });
+export const supporterState = writable<SupporterState>({ status: 'idle' });
 
 function notExpired(expires: string | null | undefined): boolean {
 	if (!expires) return true; // lifetime key
@@ -50,12 +70,12 @@ function notExpired(expires: string | null | undefined): boolean {
 }
 
 /**
- * Whether premium content should be shown. A live "valid"/"invalid" result wins;
- * otherwise we fall back to the cached result (so a reload or a brief network
- * blip doesn't lock a paying user out).
+ * Whether supporter content should be shown. A live "valid"/"invalid" result
+ * wins; otherwise we fall back to the cached result (so a reload or a brief
+ * network blip doesn't lock a paying user out).
  */
-export const isPremium = derived(
-	[premiumState, storedPremiumCache],
+export const isSupporter = derived(
+	[supporterState, storedSupporterCache],
 	([$state, $cache]): boolean => {
 		if ($state.status === 'valid') return true;
 		if ($state.status === 'invalid') return false;
@@ -78,11 +98,11 @@ export interface VerifyResult {
 export async function verifyKey(key: string): Promise<VerifyResult> {
 	const trimmed = key.trim();
 	if (!trimmed) {
-		premiumState.set({ status: 'invalid' });
+		supporterState.set({ status: 'invalid' });
 		return { valid: false, error: 'Enter your access key.' };
 	}
 
-	premiumState.set({ status: 'checking' });
+	supporterState.set({ status: 'checking' });
 	try {
 		const res = await fetch(`${PAYWALL_API_BASE}/verify?key=${encodeURIComponent(trimmed)}`, {
 			headers: { accept: 'application/json' }
@@ -91,39 +111,39 @@ export async function verifyKey(key: string): Promise<VerifyResult> {
 
 		if (res.ok && data.valid) {
 			storedLicenseKey.set(trimmed);
-			storedPremiumCache.set({
+			storedSupporterCache.set({
 				valid: true,
 				tier: data.tier,
 				expires: data.expires ?? null,
 				checkedAt: Date.now()
 			});
-			premiumState.set({ status: 'valid', tier: data.tier, expires: data.expires ?? null });
+			supporterState.set({ status: 'valid', tier: data.tier, expires: data.expires ?? null });
 			return { valid: true, tier: data.tier, expires: data.expires ?? null };
 		}
 
-		storedPremiumCache.set({ valid: false, checkedAt: Date.now() });
-		premiumState.set({ status: 'invalid' });
+		storedSupporterCache.set({ valid: false, checkedAt: Date.now() });
+		supporterState.set({ status: 'invalid' });
 		return { valid: false };
 	} catch (err) {
 		const message = err instanceof Error ? err.message : String(err);
-		premiumState.set({ status: 'error', error: message });
+		supporterState.set({ status: 'error', error: message });
 		return { valid: false, error: message };
 	}
 }
 
 /** Re-verify the stored key (call on app / gated-page load). No-op if signed out. */
-export async function refreshPremium(): Promise<void> {
+export async function refreshSupporter(): Promise<void> {
 	const key = get(storedLicenseKey);
 	if (!key) {
-		premiumState.set({ status: 'idle' });
+		supporterState.set({ status: 'idle' });
 		return;
 	}
 	await verifyKey(key);
 }
 
-/** Forget the key and premium state ("sign out"). */
+/** Forget the key and supporter state ("sign out"). */
 export function clearLicense(): void {
 	storedLicenseKey.set('');
-	storedPremiumCache.set(null);
-	premiumState.set({ status: 'idle' });
+	storedSupporterCache.set(null);
+	supporterState.set({ status: 'idle' });
 }
diff --git a/src/lib/services/weather.ts b/src/lib/services/weather.ts
index f612b07..8c6eb5d 100644
--- a/src/lib/services/weather.ts
+++ b/src/lib/services/weather.ts
@@ -23,6 +23,7 @@ import type { VariablesWithTime } from '@openmeteo/sdk/variables-with-time';
 const FORECAST_URL = 'https://api.open-meteo.com/v1/forecast';
 const ENSEMBLE_URL = 'https://ensemble-api.open-meteo.com/v1/ensemble';
 const ARCHIVE_URL = 'https://archive-api.open-meteo.com/v1/archive';
+const SEASONAL_URL = 'https://seasonal-api.open-meteo.com/v1/seasonal';
 
 // ─── Core Helpers ───────────────────────────────────────────────────────────────
 
@@ -1143,3 +1144,197 @@ export async function fetchClimateNormals(params: ClimateNormalsParams): Promise
 		precipitation_unit: params.precipitation_unit ?? 'mm'
 	};
 }
+
+// ─── Seasonal (Long-Range) Types ────────────────────────────────────────────
+
+/**
+ * One daily variable of the seasonal ensemble: every member plus the spread
+ * statistics the outlook renders (percentile band, mean, extremes).
+ */
+export interface SeasonalVariableData {
+	/** Raw members, `members[m][t]`. */
+	members: number[][];
+	mean: number[];
+	min: number[];
+	max: number[];
+	p25: number[];
+	p75: number[];
+	unit: string;
+}
+
+export interface SeasonalForecastParams extends WeatherLocation, WeatherUnitParams {
+	/** Daily API variables to request; defaults to SEASONAL_DAILY_VARS. */
+	dailyVariables?: string[];
+	/** Lead time in days; the API allows at most 216. */
+	forecast_days?: number;
+}
+
+export interface SeasonalForecastResult {
+	variables: Record<string, SeasonalVariableData>;
+	/** Milliseconds, one entry per day (already trimmed to the model's horizon). */
+	timestamps: number[];
+	/**
+	 * Local wall time (local midnight) expressed as a UTC instant - read these
+	 * with the UTC getters, never with the location's IANA zone. The seasonal API
+	 * keeps ONE offset for the whole series, so a half-year range that crosses a
+	 * DST change would otherwise land two days on the same local date.
+	 */
+	dailyDates: Date[];
+	/** `YYYY-MM-DD` local calendar date per day, matching the API's own labels. */
+	dateKeys: string[];
+	memberCount: number;
+	utcOffsetSeconds: number;
+	timezone: string;
+}
+
+/** The API caps the lead time here; the model itself usually stops earlier. */
+export const SEASONAL_MAX_DAYS = 216;
+
+/** Requested in this order; the daily block returns variables positionally. */
+export const SEASONAL_DAILY_VARS = [
+	'temperature_2m_max',
+	'temperature_2m_min',
+	'temperature_2m_mean',
+	'precipitation_sum',
+	'wind_speed_10m_mean',
+	'cloud_cover_mean'
+] as const;
+
+// ─── Seasonal (Long-Range) Fetch ────────────────────────────────────────────
+
+/** Linear-interpolated percentile over an already ascending array. */
+function percentileSorted(sorted: number[], p: number): number {
+	if (sorted.length === 0) return NaN;
+	if (sorted.length === 1) return sorted[0];
+	const pos = (sorted.length - 1) * p;
+	const lo = Math.floor(pos);
+	const hi = Math.ceil(pos);
+	if (lo === hi) return sorted[lo];
+	return sorted[lo] + (sorted[hi] - sorted[lo]) * (pos - lo);
+}
+
+/**
+ * Fetches the seasonal (multi-month) ensemble outlook from Open-Meteo's
+ * seasonal API. Unlike the medium-range ensemble this is daily data: each
+ * requested variable comes back once per member, so the members are collapsed
+ * into the spread statistics the outlook page plots.
+ *
+ * The requested lead time is only an upper bound - the model's own horizon is
+ * shorter, and every day past it comes back empty. Those trailing days are
+ * trimmed here so callers never plot a flat-lined tail.
+ */
+export async function fetchSeasonalForecast(
+	params: SeasonalForecastParams
+): Promise<SeasonalForecastResult> {
+	const dailyVars =
+		params.dailyVariables && params.dailyVariables.length > 0
+			? [...new Set(params.dailyVariables)]
+			: [...SEASONAL_DAILY_VARS];
+
+	const apiParams: Record<string, string | number | undefined> = {
+		latitude: params.latitude,
+		longitude: params.longitude,
+		daily: dailyVars.join(','),
+		forecast_days: Math.min(params.forecast_days ?? SEASONAL_MAX_DAYS, SEASONAL_MAX_DAYS),
+		temperature_unit: params.temperature_unit ?? 'celsius',
+		wind_speed_unit: params.wind_speed_unit ?? 'kmh',
+		precipitation_unit: params.precipitation_unit ?? 'mm',
+		timezone: params.timezone
+	};
+
+	const cleanParams: Record<string, string> = {};
+	for (const [key, value] of Object.entries(apiParams)) {
+		if (value !== undefined) cleanParams[key] = String(value);
+	}
+
+	const responses = await fetchWeatherApi(SEASONAL_URL, cleanParams);
+	const response = responses[0];
+	const utcOffsetSeconds = response.utcOffsetSeconds();
+	const timezone = response.timezone() ?? params.timezone ?? 'UTC';
+
+	const dailyBlock = response.daily()!;
+	const allTimestamps = getTimestamps(dailyBlock);
+	const timeLength = allTimestamps.length;
+
+	// Members are laid out like the ensemble API: var0_member0 … var0_memberM-1,
+	// var1_member0 …, so the count follows from the totals instead of being
+	// hard-coded (it differs per seasonal model).
+	const totalVariables = dailyBlock.variablesLength();
+	const memberCount = dailyVars.length > 0 ? Math.floor(totalVariables / dailyVars.length) : 0;
+
+	const variables: Record<string, SeasonalVariableData> = {};
+
+	for (let vi = 0; vi < dailyVars.length; vi++) {
+		const members: number[][] = [];
+		let unitStr = '';
+
+		for (let mi = 0; mi < memberCount; mi++) {
+			const variable = dailyBlock.variables(vi * memberCount + mi);
+			if (!variable) continue;
+			members.push(getValues(variable));
+			if (mi === 0) unitStr = unitToDisplayString(variable.unit());
+		}
+
+		const mean = new Array<number>(timeLength).fill(NaN);
+		const min = new Array<number>(timeLength).fill(NaN);
+		const max = new Array<number>(timeLength).fill(NaN);
+		const p25 = new Array<number>(timeLength).fill(NaN);
+		const p75 = new Array<number>(timeLength).fill(NaN);
+
+		for (let t = 0; t < timeLength; t++) {
+			const values: number[] = [];
+			for (const memberValues of members) {
+				const val = memberValues[t];
+				if (val != null && Number.isFinite(val)) values.push(val);
+			}
+			if (values.length === 0) continue;
+			values.sort((a, b) => a - b);
+			mean[t] = values.reduce((a, b) => a + b, 0) / values.length;
+			min[t] = values[0];
+			max[t] = values[values.length - 1];
+			p25[t] = percentileSorted(values, 0.25);
+			p75[t] = percentileSorted(values, 0.75);
+		}
+
+		variables[dailyVars[vi]] = { members, mean, min, max, p25, p75, unit: unitStr };
+	}
+
+	// Past the model's horizon every member is empty (or padded to a constant
+	// zero); cut the axis at the last day that carries real spread.
+	const sentinel = variables[dailyVars[0]];
+	let validLength = timeLength;
+	if (sentinel) {
+		let last = 0;
+		for (let t = 0; t < timeLength; t++) {
+			const hasSpread = !(sentinel.min[t] === 0 && sentinel.max[t] === 0);
+			if (Number.isFinite(sentinel.mean[t]) && hasSpread) last = t + 1;
+		}
+		validLength = last || timeLength;
+	}
+
+	if (validLength < timeLength) {
+		for (const data of Object.values(variables)) {
+			data.members = data.members.map((m) => m.slice(0, validLength));
+			data.mean = data.mean.slice(0, validLength);
+			data.min = data.min.slice(0, validLength);
+			data.max = data.max.slice(0, validLength);
+			data.p25 = data.p25.slice(0, validLength);
+			data.p75 = data.p75.slice(0, validLength);
+		}
+	}
+
+	const timestamps = allTimestamps.slice(0, validLength);
+	// Shifted by the response's single offset (not the IANA zone) so each day
+	// carries the exact local date the API labelled it with.
+	const dailyDates = timestamps.map((t) => new Date(t + utcOffsetSeconds * 1000));
+
+	return {
+		variables,
+		timestamps,
+		dailyDates,
+		dateKeys: dailyDates.map((d) => d.toISOString().slice(0, 10)),
+		memberCount,
+		utcOffsetSeconds,
+		timezone
+	};
+}
diff --git a/src/routes/weather/historical/[location]/+page.svelte b/src/routes/weather/historical/[location]/+page.svelte
index 3889f1b..5557bcc 100644
--- a/src/routes/weather/historical/[location]/+page.svelte
+++ b/src/routes/weather/historical/[location]/+page.svelte
@@ -13,7 +13,7 @@
 	import { ChartContainer } from '$lib/components/charts';
 
 	import PaywallGate from '$lib/paywall/PaywallGate.svelte';
-	import { isPremium } from '$lib/paywall/premium';
+	import { isSupporter } from '$lib/paywall/supporter';
 	import {
 		type ClimateNormals,
 		type HistoricalForecastResult,
@@ -97,7 +97,7 @@
 		const s = startDate;
 		const e = endDate;
 		const vars = hourlyVars;
-		if (!mounted || !$isPremium || !loc || !s || !e) return;
+		if (!mounted || !$isSupporter || !loc || !s || !e) return;
 
 		const version = ++requestVersion;
 		loading = true;
@@ -138,7 +138,7 @@
 	$effect(() => {
 		const key = normalsKey;
 		const loc = location;
-		if (!mounted || !$isPremium || !loc) return;
+		if (!mounted || !$isSupporter || !loc) return;
 
 		const version = ++normalsVersion;
 		normals = null;
diff --git a/src/routes/weather/seasonal/+page.svelte b/src/routes/weather/seasonal/+page.svelte
new file mode 100644
index 0000000..6486548
--- /dev/null
+++ b/src/routes/weather/seasonal/+page.svelte
@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { onMount } from 'svelte';
+	import { get } from 'svelte/store';
+
+	import { goto } from '$app/navigation';
+	import { resolve } from '$app/paths';
+
+	import { storedLocation } from '$lib/stores/settings';
+
+	import { buildLocationRoute } from '$lib/utils/location';
+
+	// at build time this page knows nothing about the visitor, so the redirect
+	// target (the persisted location) is resolved in the browser instead of
+	// being baked to the default city during prerender
+	onMount(() => {
+		goto(
+			resolve('/weather/seasonal/[location]', {
+				location: buildLocationRoute(get(storedLocation))
+			}),
+			{ replaceState: true }
+		);
+	});
+</script>
diff --git a/src/routes/weather/seasonal/[location]/+page.svelte b/src/routes/weather/seasonal/[location]/+page.svelte
new file mode 100644
index 0000000..58f57bb
--- /dev/null
+++ b/src/routes/weather/seasonal/[location]/+page.svelte
@@ -0,0 +1,296 @@
+<script lang="ts">
+	import { onMount } from 'svelte';
+	import { fade } from 'svelte/transition';
+
+	import { storedLocation, storedUnits } from '$lib/stores/settings';
+
+	import { ChartContainer, ChartToolbar } from '$lib/components/charts';
+	import { Label } from '$lib/components/ui/label';
+	import { Switch } from '$lib/components/ui/switch';
+
+	import PaywallGate from '$lib/paywall/PaywallGate.svelte';
+	import { isSupporter } from '$lib/paywall/supporter';
+	import {
+		type ClimateNormals,
+		type SeasonalForecastResult,
+		fetchClimateNormals,
+		fetchSeasonalForecast
+	} from '$lib/services/weather';
+
+	import { defaultParameters } from '../../options';
+	import { getPrecipUnit } from '../../week/[location]/types';
+	import SeasonalCharts from './SeasonalCharts.svelte';
+	import SeasonalMonths from './SeasonalMonths.svelte';
+	import { buildMonthOutlooks, sliceSeasonal } from './outlook';
+
+	import type { CanvasChart } from '$lib/charts';
+	import type { PageData } from './$types';
+
+	let { data }: { data: PageData } = $props();
+
+	// the URL is the source of truth: location comes from the load function,
+	// which is also correct on hydrated prerendered pages. The persisted store
+	// only mirrors it so the header and bare /weather/* redirects follow along.
+	let location = $derived(data.location);
+	$effect(() => {
+		storedLocation.set(data.location);
+	});
+
+	let params = $state({ ...defaultParameters });
+	$effect(() => {
+		params.temperature_unit = $storedUnits.temperature_unit;
+		params.wind_speed_unit = $storedUnits.wind_speed_unit;
+		params.precipitation_unit = $storedUnits.precipitation_unit;
+	});
+
+	// Only the variables the outlook actually renders: every extra one costs a
+	// full member set (50+ series) over half a year of days.
+	const SEASONAL_VARS = [
+		'temperature_2m_max',
+		'temperature_2m_min',
+		'temperature_2m_mean',
+		'precipitation_sum'
+	];
+
+	// ─── Display state (no refetch) ─────────────────────────────────────────────
+	const RANGES = [
+		{ label: '3 months', days: 92 },
+		{ label: '6 months', days: 183 },
+		{ label: 'Full range', days: Infinity }
+	];
+	let rangeIndex = $state(1);
+	let showLegend = $state(true);
+	let chartComponents: CanvasChart[] = $state([]);
+	let liveCharts = $derived(chartComponents.filter((chart) => chart != null));
+
+	// ─── Fetch state ────────────────────────────────────────────────────────────
+	let mounted = $state(false);
+	let loading = $state(true);
+	let loadError = $state<string | null>(null);
+	let requestVersion = 0;
+
+	let result = $state<SeasonalForecastResult | null>(null);
+	let normals = $state<ClimateNormals | null>(null);
+
+	onMount(() => {
+		mounted = true;
+	});
+
+	// The full horizon is fetched once per location/units; the range buttons only
+	// reslice it.
+	$effect(() => {
+		const loc = location;
+		const tempUnit = params.temperature_unit;
+		const precipUnit = params.precipitation_unit;
+		if (!mounted || !$isSupporter || !loc) return;
+
+		const version = ++requestVersion;
+		loading = true;
+		loadError = null;
+
+		fetchSeasonalForecast({
+			latitude: loc.latitude!,
+			longitude: loc.longitude!,
+			dailyVariables: SEASONAL_VARS,
+			temperature_unit: tempUnit as 'celsius' | 'fahrenheit',
+			wind_speed_unit: params.wind_speed_unit as 'kmh' | 'ms' | 'mph' | 'kn',
+			precipitation_unit: precipUnit as 'mm' | 'inch',
+			timezone: loc.timezone
+		})
+			.then((r) => {
+				if (version !== requestVersion) return;
+				result = r;
+				loading = false;
+			})
+			.catch((err: unknown) => {
+				if (version !== requestVersion) return;
+				loadError = err instanceof Error ? err.message : String(err);
+				loading = false;
+			});
+	});
+
+	// Normals are the whole point of a seasonal outlook (everything is shown as a
+	// departure from them), but a failure only drops the comparison.
+	let normalsKey = $derived(
+		`${location?.latitude},${location?.longitude},${params.temperature_unit},${params.precipitation_unit}`
+	);
+	let normalsVersion = 0;
+	$effect(() => {
+		const key = normalsKey;
+		const loc = location;
+		if (!mounted || !$isSupporter || !loc) return;
+
+		const version = ++normalsVersion;
+		normals = null;
+		fetchClimateNormals({
+			latitude: loc.latitude!,
+			longitude: loc.longitude!,
+			temperature_unit: params.temperature_unit as 'celsius' | 'fahrenheit',
+			precipitation_unit: params.precipitation_unit as 'mm' | 'inch'
+		})
+			.then((n) => {
+				if (version === normalsVersion) normals = n;
+			})
+			.catch(() => {
+				if (version === normalsVersion) normals = null;
+			});
+		void key;
+	});
+
+	// ─── Derived view ───────────────────────────────────────────────────────────
+	let visible = $derived(result ? sliceSeasonal(result, RANGES[rangeIndex].days) : null);
+
+	// 1 mm and 0.04 in are the same "measurable rain" threshold in either unit.
+	let wetDayThreshold = $derived(getPrecipUnit(params) === 'in' ? 0.04 : 1);
+
+	let months = $derived(visible ? buildMonthOutlooks(visible, normals, { wetDayThreshold }) : []);
+
+	let horizonDays = $derived(result?.timestamps.length ?? 0);
+	let lastDay = $derived(
+		visible && visible.dailyDates.length > 0
+			? visible.dailyDates[visible.dailyDates.length - 1]
+			: null
+	);
+	// dailyDates are local wall time held as UTC instants (see the service), so
+	// the label has to be formatted in UTC to read back the local date.
+	let lastDayLabel = $derived(
+		lastDay
+			? lastDay.toLocaleDateString(undefined, {
+					month: 'long',
+					day: 'numeric',
+					year: 'numeric',
+					timeZone: 'UTC'
+				})
+			: ''
+	);
+</script>
+
+<svelte:head>
+	<title>Drizz.li | Seasonal forecast</title>
+	<meta
+		name="description"
+		content="Multi-month seasonal outlook: monthly temperature and precipitation trends against the 1991-2020 climate normal"
+	/>
+</svelte:head>
+
+<!-- Page hero -->
+<div class="relative mb-3 flex flex-wrap items-center justify-between gap-x-6 gap-y-3 md:mb-5">
+	<div class="flex min-w-0 items-center gap-3">
+		<img
+			class="h-10 w-10 shrink-0 rounded-full shadow-sm ring-2 ring-border"
+			src="/images/country-flags/{(location.country_code || 'united_nations').toLowerCase()}.svg"
+			alt={location.country ?? ''}
+		/>
+		<div class="min-w-0">
+			<h1 class="truncate text-2xl leading-tight font-bold tracking-tight md:text-3xl">
+				{location.name}
+			</h1>
+			<p class="truncate text-sm text-muted-foreground">
+				<span class="lg:hidden"
+					>{#if location.admin1}{location.admin1},
+					{/if}{location.country ?? ''}<span class="mx-1 opacity-50">·</span></span
+				>Seasonal outlook
+			</p>
+		</div>
+	</div>
+
+	{#if result}
+		<!-- range buttons reslice the already-fetched horizon (no refetch) -->
+		<div
+			class="flex w-full gap-1 rounded-lg border border-border bg-card p-1 sm:w-auto"
+			role="group"
+			aria-label="Outlook range"
+		>
+			{#each RANGES as range, i (range.label)}
+				{@const disabled = range.days !== Infinity && range.days > horizonDays}
+				<button
+					type="button"
+					class="flex-1 cursor-pointer rounded-md px-3 py-1.5 text-xs font-semibold whitespace-nowrap transition-colors sm:flex-none {rangeIndex ===
+					i
+						? 'bg-primary text-primary-foreground'
+						: 'text-muted-foreground hover:bg-muted hover:text-foreground'} {disabled
+						? 'cursor-not-allowed opacity-40'
+						: ''}"
+					aria-pressed={rangeIndex === i}
+					{disabled}
+					onclick={() => (rangeIndex = i)}
+				>
+					{range.label}
+				</button>
+			{/each}
+		</div>
+	{/if}
+</div>
+
+<!-- What a seasonal forecast is (and is not): without this the daily-looking
+     charts invite over-reading. -->
+<div
+	class="mb-4 flex items-start gap-2.5 rounded-md border border-border bg-muted/40 px-3.5 py-2.5 text-sm"
+>
+	<svg
+		class="mt-0.5 h-4 w-4 shrink-0 text-muted-foreground"
+		fill="none"
+		stroke="currentColor"
+		viewBox="0 0 24 24"
+		stroke-width="2"
+	>
+		<path stroke-linecap="round" stroke-linejoin="round" d="M12 16v-4m0-4h.01" />
+		<circle cx="12" cy="12" r="9" />
+	</svg>
+	<p class="text-muted-foreground">
+		A seasonal forecast shows how a whole month is likely to
+		<strong class="font-semibold text-foreground">depart from its climate normal</strong> - not the
+		weather on any given day. Read the monthly trend and the ensemble agreement, not the daily
+		wiggles.
+		{#if lastDayLabel}
+			This outlook runs to <strong class="font-semibold text-foreground">{lastDayLabel}</strong>.
+		{/if}
+	</p>
+</div>
+
+<PaywallGate feature="The seasonal outlook">
+	{#if loadError}
+		<div
+			class="mb-4 rounded-md border border-destructive/50 bg-destructive/10 px-4 py-3 text-sm text-destructive"
+		>
+			Failed to load the seasonal outlook: {loadError}
+		</div>
+	{/if}
+
+	{#if visible && months.length > 0}
+		<SeasonalMonths {months} units={params} {normals} />
+
+		<div class="mt-6">
+			<SeasonalCharts
+				result={visible}
+				{normals}
+				units={params}
+				{loading}
+				{showLegend}
+				bind:charts={chartComponents}
+			/>
+		</div>
+
+		<div class="mt-6 md:mt-10">
+			<ChartToolbar charts={liveCharts} fileName="seasonal-outlook">
+				{#snippet controls()}
+					<div class="flex items-center gap-2">
+						<Switch id="show_legend" name="Show legend" bind:checked={showLegend} />
+						<Label for="show_legend" class="cursor-pointer text-base leading-none"
+							>Show legend</Label
+						>
+					</div>
+				{/snippet}
+			</ChartToolbar>
+		</div>
+	{:else if !loadError}
+		<div transition:fade={{ duration: 200 }} class="grid gap-3">
+			<div class="grid gap-2.5 sm:grid-cols-2 lg:grid-cols-3">
+				{#each [0, 1, 2, 3, 4, 5] as i (i)}
+					<div class="h-44 animate-pulse rounded-xl border border-border/70 bg-card"></div>
+				{/each}
+			</div>
+			<ChartContainer loading chartCount={2} chartHeight={300} bleed={false} />
+		</div>
+	{/if}
+</PaywallGate>
diff --git a/src/routes/weather/seasonal/[location]/+page.ts b/src/routes/weather/seasonal/[location]/+page.ts
new file mode 100644
index 0000000..a6b5eb8
--- /dev/null
+++ b/src/routes/weather/seasonal/[location]/+page.ts
@@ -0,0 +1,13 @@
+import { resolveLocationFromRoute } from '$lib/utils/location';
+
+import type { PageLoad } from './$types';
+
+export const load: PageLoad = async (event) => {
+	const location = await resolveLocationFromRoute({
+		urlLocation: event.params.location,
+		routePrefix: '/weather/seasonal/',
+		event
+	});
+
+	return { location };
+};
diff --git a/src/routes/weather/seasonal/[location]/SeasonalCharts.svelte b/src/routes/weather/seasonal/[location]/SeasonalCharts.svelte
new file mode 100644
index 0000000..7821a8f
--- /dev/null
+++ b/src/routes/weather/seasonal/[location]/SeasonalCharts.svelte
@@ -0,0 +1,211 @@
+<script lang="ts">
+	import { ChartContainer } from '$lib/components/charts';
+
+	import { CHART_COLORS, CanvasChart, type ChartSeries } from '$lib/charts';
+	import {
+		type ClimateNormals,
+		type SeasonalForecastResult,
+		monthDayToOrdinal
+	} from '$lib/services/weather';
+
+	import { type WeatherUnits, getPrecipUnit, getTempUnit } from '../../week/[location]/types';
+	import { rollingMean, rollingSum } from './outlook';
+
+	interface Props {
+		result: SeasonalForecastResult;
+		normals: ClimateNormals | null;
+		units: WeatherUnits;
+		loading?: boolean;
+		showLegend?: boolean;
+		/** Smoothing window in days, shared by both charts. */
+		smoothing?: number;
+		charts?: CanvasChart[];
+	}
+
+	let {
+		result,
+		normals,
+		units,
+		loading = false,
+		showLegend = true,
+		smoothing = 7,
+		charts = $bindable([])
+	}: Props = $props();
+
+	const CHART_GROUP = 'seasonal-outlook';
+	const SPREAD_COLOR = 'rgba(115, 192, 222, 0.75)';
+	const BAND_COLOR = 'rgba(56, 132, 189, 0.9)';
+	const NORMAL_COLOR = '#9ca3af';
+
+	const tempUnit = $derived(getTempUnit(units));
+	const precipUnit = $derived(getPrecipUnit(units));
+
+	// CanvasChart works in epoch seconds. The axis is fed local wall time (and
+	// labelled in UTC) because the seasonal series carries a single fixed offset:
+	// resolving it against the IANA zone would slide every date past a DST change.
+	let timestamps = $derived(result.dailyDates.map((d) => d.getTime() / 1000));
+
+	// Climate normal for each forecast day, so it can be drawn as a reference
+	// line on the same axis as the ensemble.
+	let ordinals = $derived(
+		result.dateKeys.map((key) =>
+			monthDayToOrdinal(Number(key.slice(5, 7)), Number(key.slice(8, 10)))
+		)
+	);
+	let normalTemp = $derived(normals ? ordinals.map((o) => normals.tmean[o]) : null);
+	let normalPrecip = $derived(normals ? ordinals.map((o) => normals.precip[o]) : null);
+
+	const fmt =
+		(unit: string, digits = 1) =>
+		(v: number) =>
+			`${v.toFixed(digits)} ${unit}`;
+
+	let tempSeries = $derived.by((): ChartSeries[] => {
+		const v = result.variables['temperature_2m_mean'];
+		if (!v) return [];
+		const smooth = (xs: number[]) => rollingMean(xs, smoothing);
+
+		const series: ChartSeries[] = [
+			{
+				name: 'Full spread',
+				type: 'line',
+				color: SPREAD_COLOR,
+				data: smooth(v.max),
+				width: 0,
+				fill: true,
+				fillOpacity: 0.16,
+				bandTo: smooth(v.min),
+				shortName: 'spread',
+				format: fmt(tempUnit)
+			},
+			{
+				name: 'Likely range (25-75%)',
+				type: 'line',
+				color: BAND_COLOR,
+				data: smooth(v.p75),
+				width: 0,
+				fill: true,
+				fillOpacity: 0.3,
+				bandTo: smooth(v.p25),
+				shortName: 'likely',
+				format: fmt(tempUnit)
+			},
+			{
+				name: 'Ensemble mean',
+				type: 'line',
+				color: CHART_COLORS.average,
+				data: smooth(v.mean),
+				width: 3,
+				outline: true,
+				format: fmt(tempUnit)
+			}
+		];
+
+		if (normalTemp) {
+			series.push({
+				name: 'Climate normal',
+				type: 'line',
+				color: NORMAL_COLOR,
+				data: smooth(normalTemp),
+				width: 2,
+				dashed: true,
+				shortName: 'normal',
+				format: fmt(tempUnit)
+			});
+		}
+
+		return series;
+	});
+
+	let precipSeries = $derived.by((): ChartSeries[] => {
+		const v = result.variables['precipitation_sum'];
+		if (!v) return [];
+		const total = (xs: number[]) => rollingSum(xs, smoothing);
+
+		const series: ChartSeries[] = [
+			{
+				name: 'Likely range (25-75%)',
+				type: 'line',
+				color: BAND_COLOR,
+				data: total(v.p75),
+				width: 0,
+				fill: true,
+				fillOpacity: 0.28,
+				bandTo: total(v.p25),
+				shortName: 'likely',
+				format: fmt(precipUnit)
+			},
+			{
+				name: 'Ensemble mean',
+				type: 'line',
+				color: CHART_COLORS.average,
+				data: total(v.mean),
+				width: 3,
+				outline: true,
+				format: fmt(precipUnit)
+			}
+		];
+
+		if (normalPrecip) {
+			series.push({
+				name: 'Climate normal',
+				type: 'line',
+				color: NORMAL_COLOR,
+				data: total(normalPrecip),
+				width: 2,
+				dashed: true,
+				shortName: 'normal',
+				format: fmt(precipUnit)
+			});
+		}
+
+		return series;
+	});
+
+	let chartDefs = $derived(
+		[
+			{
+				title: 'Temperature outlook',
+				subtitle: `${smoothing}-day smoothed daily mean · ${result.memberCount} ensemble members`,
+				unit: tempUnit,
+				series: tempSeries,
+				zeroBaseLeft: false,
+				showCredit: false
+			},
+			{
+				title: 'Precipitation outlook',
+				subtitle: `${smoothing}-day rolling total (${precipUnit})`,
+				unit: precipUnit,
+				series: precipSeries,
+				zeroBaseLeft: true,
+				showCredit: true
+			}
+		].filter((def) => def.series.length > 0)
+	);
+</script>
+
+<!-- full-bleed graphs until lg / contained card on lg+ (matches the 14-day page) -->
+<div class="-mx-3 border-y border-border/70 bg-card shadow-sm lg:mx-0 lg:rounded-2xl lg:border">
+	{#each chartDefs as def, i (def.title)}
+		<div class="px-0 pt-1.5 pb-1 lg:px-4 lg:pb-3 {i > 0 ? 'border-t border-border/50' : ''}">
+			<div class="mb-1 px-3 lg:px-0">
+				<h4 class="text-sm font-bold tracking-tight">{def.title}</h4>
+				<p class="text-xs text-muted-foreground">{def.subtitle}</p>
+			</div>
+			<ChartContainer {loading} chartCount={1} chartHeight={300} minWidth={520} bleed={false}>
+				<CanvasChart
+					bind:this={charts[i]}
+					{timestamps}
+					timezone="UTC"
+					series={def.series}
+					unit={def.unit}
+					zeroBaseLeft={def.zeroBaseLeft}
+					showCredit={def.showCredit}
+					{showLegend}
+					height={300}
+					group={CHART_GROUP}
+				/>
+			</ChartContainer>
+		</div>
+	{/each}
+</div>
diff --git a/src/routes/weather/seasonal/[location]/SeasonalMonths.svelte b/src/routes/weather/seasonal/[location]/SeasonalMonths.svelte
new file mode 100644
index 0000000..9d0b04d
--- /dev/null
+++ b/src/routes/weather/seasonal/[location]/SeasonalMonths.svelte
@@ -0,0 +1,150 @@
+<script lang="ts">
+	import { getColor } from '../../utils/colors';
+	import { type WeatherUnits, getPrecipUnit, getTempUnit } from '../../week/[location]/types';
+
+	import type { ClimateNormals } from '$lib/services/weather';
+	import type { MonthOutlook } from './outlook';
+
+	interface Props {
+		months: MonthOutlook[];
+		units: WeatherUnits;
+		normals: ClimateNormals | null;
+	}
+
+	let { months, units, normals }: Props = $props();
+
+	const tempUnit = $derived(getTempUnit(units));
+	const precipUnit = $derived(getPrecipUnit(units));
+
+	const finite = (v: number | null | undefined): v is number => v != null && Number.isFinite(v);
+	const fmtTemp = (v: number): string => (finite(v) ? `${v.toFixed(1)}°` : '–');
+	const fmtSigned = (v: number): string => `${v >= 0 ? '+' : ''}${v.toFixed(1)}°`;
+	const fmtPrecip = (v: number): string => `${v.toFixed(v < 10 ? 1 : 0)}`;
+
+	// Members agreeing on the sign of the anomaly is the honest confidence signal
+	// for a seasonal outlook: a big anomaly that only half the members share means
+	// nothing. Below this the card says so instead of implying a trend.
+	const AGREEMENT_FLOOR = 0.6;
+
+	function anomalyLabel(delta: number): string {
+		const a = Math.abs(delta);
+		if (a < 0.3) return 'near normal';
+		const word = a < 1 ? 'slightly' : a < 2.5 ? '' : 'well';
+		return `${word} ${delta > 0 ? 'above' : 'below'} normal`.replace(/\s+/g, ' ').trim();
+	}
+</script>
+
+<div class="grid gap-2.5 sm:grid-cols-2 lg:grid-cols-3">
+	{#each months as month (month.key)}
+		{@const agree = Math.max(month.warmerShare, 1 - month.warmerShare)}
+		{@const confident = agree >= AGREEMENT_FLOOR}
+		<article class="rounded-xl border border-border/70 bg-card p-3.5 shadow-sm">
+			<div class="flex items-baseline justify-between gap-2">
+				<h3 class="text-base font-bold tracking-tight">{month.label}</h3>
+				<span class="text-xs text-muted-foreground">
+					{month.days}
+					{month.days === 1 ? 'day' : 'days'}{month.partial ? ' (partial)' : ''}
+				</span>
+			</div>
+
+			<!-- headline: mean temperature and its departure from the 1991-2020 normal -->
+			<div class="mt-2.5 flex items-end gap-3">
+				<div>
+					<p class="text-xs font-medium text-muted-foreground">Mean temperature</p>
+					<p class="text-2xl leading-tight font-bold tabular-nums">
+						{fmtTemp(month.tMean)}<span class="text-base font-semibold text-muted-foreground"
+							>{tempUnit.replace('°', '')}</span
+						>
+					</p>
+				</div>
+				<div class="ml-auto text-right">
+					{#if finite(month.anomaly)}
+						<p
+							class="text-lg leading-tight font-bold tabular-nums"
+							class:text-red-600={month.anomaly >= 0}
+							class:text-blue-600={month.anomaly < 0}
+							class:dark:text-red-400={month.anomaly >= 0}
+							class:dark:text-blue-400={month.anomaly < 0}
+						>
+							{fmtSigned(month.anomaly)}
+						</p>
+						<p class="text-[11px] text-muted-foreground">{anomalyLabel(month.anomaly)}</p>
+					{:else if normals}
+						<p class="text-[11px] text-muted-foreground">no normal for this month</p>
+					{:else}
+						<p class="text-[11px] text-muted-foreground">normal loading…</p>
+					{/if}
+				</div>
+			</div>
+
+			<!-- day / night means, coloured on the same temperature scale as the strip -->
+			<div class="mt-2.5 flex items-center gap-2 text-xs">
+				<span class="inline-flex items-center gap-1.5">
+					<span
+						class="inline-block h-2.5 w-2.5 rounded-full"
+						style="background:{getColor(month.tMax, units.temperature_unit)}"
+					></span>
+					<span class="font-semibold tabular-nums">{fmtTemp(month.tMax)}</span>
+					<span class="text-muted-foreground">day</span>
+				</span>
+				<span class="inline-flex items-center gap-1.5">
+					<span
+						class="inline-block h-2.5 w-2.5 rounded-full"
+						style="background:{getColor(month.tMin, units.temperature_unit)}"
+					></span>
+					<span class="font-semibold tabular-nums">{fmtTemp(month.tMin)}</span>
+					<span class="text-muted-foreground">night</span>
+				</span>
+			</div>
+
+			<!-- precipitation against its own normal, as a share bar -->
+			<div class="mt-3 border-t border-border/60 pt-2.5">
+				<div class="flex items-baseline justify-between gap-2 text-xs">
+					<span class="font-medium text-muted-foreground">Precipitation</span>
+					<span class="font-semibold tabular-nums">
+						{fmtPrecip(month.precip)}
+						{precipUnit}
+						{#if finite(month.precipNormal)}
+							<span class="font-medium text-muted-foreground">
+								/ normal {fmtPrecip(month.precipNormal)}
+							</span>
+						{/if}
+					</span>
+				</div>
+				{#if finite(month.precipShare)}
+					{@const pct = Math.min(200, month.precipShare * 100)}
+					<div class="mt-1.5 h-1.5 overflow-hidden rounded-full bg-muted">
+						<div
+							class="h-full rounded-full"
+							style="width:{pct / 2}%;background:{month.precipShare >= 1
+								? 'var(--color-sky-500, #0ea5e9)'
+								: 'var(--color-amber-500, #f59e0b)'}"
+						></div>
+					</div>
+					<p class="mt-1 text-[11px] text-muted-foreground">
+						{Math.round(month.precipShare * 100)}% of normal · {month.wetDays} wet days
+					</p>
+				{/if}
+			</div>
+
+			<!-- ensemble agreement: the actual confidence in the anomaly above -->
+			<div class="mt-2.5 flex items-center gap-2">
+				<div class="h-1.5 flex-1 overflow-hidden rounded-full bg-muted">
+					<div
+						class="h-full rounded-full"
+						class:bg-primary={confident}
+						class:bg-muted-foreground={!confident}
+						style="width:{Math.round(agree * 100)}%"
+					></div>
+				</div>
+				<span class="text-[11px] whitespace-nowrap text-muted-foreground">
+					{#if confident}
+						{Math.round(agree * 100)}% of members {month.warmerShare >= 0.5 ? 'warmer' : 'colder'}
+					{:else}
+						members split - low confidence
+					{/if}
+				</span>
+			</div>
+		</article>
+	{/each}
+</div>
diff --git a/src/routes/weather/seasonal/[location]/outlook.ts b/src/routes/weather/seasonal/[location]/outlook.ts
new file mode 100644
index 0000000..da9a1bb
--- /dev/null
+++ b/src/routes/weather/seasonal/[location]/outlook.ts
@@ -0,0 +1,199 @@
+/**
+ * Turns the raw seasonal ensemble into the per-calendar-month outlook the page
+ * shows. Seasonal models carry no day-to-day skill, so everything here is an
+ * aggregate: monthly means, the departure from the climate normal, and how much
+ * of the ensemble actually agrees on that departure.
+ */
+import {
+	type ClimateNormals,
+	type SeasonalForecastResult,
+	monthDayToOrdinal
+} from '$lib/services/weather';
+
+export interface MonthOutlook {
+	/** `YYYY-MM` in the location's local calendar. */
+	key: string;
+	/** Month name and year, e.g. "August 2026". */
+	label: string;
+	/** Forecast days covered (a leading/trailing month is usually incomplete). */
+	days: number;
+	partial: boolean;
+	tMean: number;
+	tMax: number;
+	tMin: number;
+	/** Mean temperature minus the climate normal, or null without normals. */
+	anomaly: number | null;
+	precip: number;
+	precipNormal: number | null;
+	/** Forecast precipitation as a share of normal (1 = exactly normal). */
+	precipShare: number | null;
+	wetDays: number;
+	/** Share of ensemble members whose monthly mean is above the normal. */
+	warmerShare: number;
+}
+
+const finite = (v: number | null | undefined): v is number => v != null && Number.isFinite(v);
+
+// The month key already carries the local calendar month, so the label is
+// formatted in UTC - anything zone-aware would just reintroduce the shift.
+const MONTH_LABEL = new Intl.DateTimeFormat(undefined, {
+	month: 'long',
+	year: 'numeric',
+	timeZone: 'UTC'
+});
+
+const mean = (xs: number[]): number =>
+	xs.length ? xs.reduce((a, b) => a + b, 0) / xs.length : NaN;
+
+/** Days in a calendar month; `month` is 1-based. */
+function daysInMonth(year: number, month: number): number {
+	return new Date(Date.UTC(year, month, 0)).getUTCDate();
+}
+
+interface BuildOptions {
+	/** Daily total counted as a wet day, in the active precipitation unit. */
+	wetDayThreshold: number;
+}
+
+export function buildMonthOutlooks(
+	result: SeasonalForecastResult,
+	normals: ClimateNormals | null,
+	{ wetDayThreshold }: BuildOptions
+): MonthOutlook[] {
+	const tMeanVar = result.variables['temperature_2m_mean'];
+	const tMaxVar = result.variables['temperature_2m_max'];
+	const tMinVar = result.variables['temperature_2m_min'];
+	const precipVar = result.variables['precipitation_sum'];
+	if (!tMeanVar) return [];
+
+	const { dateKeys } = result;
+
+	// Day indices grouped by calendar month, plus the normals lookup per day.
+	// Both read the API's own local dates: deriving them from the instants would
+	// double-count the day a DST change falls on.
+	const groups = new Map<string, number[]>();
+	const ordinals = dateKeys.map((key) =>
+		monthDayToOrdinal(Number(key.slice(5, 7)), Number(key.slice(8, 10)))
+	);
+
+	for (let i = 0; i < dateKeys.length; i++) {
+		const key = dateKeys[i].slice(0, 7);
+		const bucket = groups.get(key);
+		if (bucket) bucket.push(i);
+		else groups.set(key, [i]);
+	}
+
+	const months: MonthOutlook[] = [];
+
+	for (const [key, indices] of groups) {
+		const pick = (values: number[] | undefined): number =>
+			values ? mean(indices.map((i) => values[i]).filter(finite)) : NaN;
+
+		const [year, month] = key.split('-').map(Number);
+
+		// Normals are per day-of-year, so the comparison uses exactly the days the
+		// forecast covers - a half month is never compared against a full one.
+		let normalMean = NaN;
+		let normalPrecip = NaN;
+		if (normals) {
+			normalMean = mean(indices.map((i) => normals.tmean[ordinals[i]]).filter(finite));
+			const np = indices.map((i) => normals.precip[ordinals[i]]).filter(finite);
+			if (np.length) normalPrecip = np.reduce((a, b) => a + b, 0);
+		}
+
+		const tMean = pick(tMeanVar.mean);
+
+		// Per-member monthly means decide the agreement share: a member counts as
+		// warmer only if it beats the same normal the anomaly is measured against.
+		let warmer = 0;
+		let counted = 0;
+		if (finite(normalMean)) {
+			for (const member of tMeanVar.members) {
+				const memberMean = mean(indices.map((i) => member[i]).filter(finite));
+				if (!finite(memberMean)) continue;
+				counted++;
+				if (memberMean > normalMean) warmer++;
+			}
+		}
+
+		const precipDays = precipVar ? indices.map((i) => precipVar.mean[i]).filter(finite) : [];
+		const precip = precipDays.reduce((a, b) => a + b, 0);
+
+		months.push({
+			key,
+			label: MONTH_LABEL.format(Date.UTC(year, month - 1, 1)),
+			days: indices.length,
+			partial: indices.length < daysInMonth(year, month),
+			tMean,
+			tMax: pick(tMaxVar?.mean),
+			tMin: pick(tMinVar?.mean),
+			anomaly: finite(normalMean) && finite(tMean) ? tMean - normalMean : null,
+			precip,
+			precipNormal: finite(normalPrecip) ? normalPrecip : null,
+			precipShare: finite(normalPrecip) && normalPrecip > 0 ? precip / normalPrecip : null,
+			wetDays: precipDays.filter((p) => p >= wetDayThreshold).length,
+			warmerShare: counted > 0 ? warmer / counted : 0.5
+		});
+	}
+
+	return months;
+}
+
+/**
+ * Narrows an outlook to its first `days` days. The fetch always asks for the
+ * model's full horizon, so the range buttons only reslice what is already in
+ * memory instead of issuing another (large) request.
+ */
+export function sliceSeasonal(
+	result: SeasonalForecastResult,
+	days: number
+): SeasonalForecastResult {
+	if (days >= result.timestamps.length) return result;
+
+	const variables: SeasonalForecastResult['variables'] = {};
+	for (const [name, data] of Object.entries(result.variables)) {
+		variables[name] = {
+			members: data.members.map((m) => m.slice(0, days)),
+			mean: data.mean.slice(0, days),
+			min: data.min.slice(0, days),
+			max: data.max.slice(0, days),
+			p25: data.p25.slice(0, days),
+			p75: data.p75.slice(0, days),
+			unit: data.unit
+		};
+	}
+
+	return {
+		...result,
+		variables,
+		timestamps: result.timestamps.slice(0, days),
+		dailyDates: result.dailyDates.slice(0, days),
+		dateKeys: result.dateKeys.slice(0, days)
+	};
+}
+
+/**
+ * Centered rolling mean. Seasonal ensembles are far too noisy to read day by
+ * day; smoothing shows the trend the model actually claims to resolve. Windows
+ * shrink at the edges instead of dropping data.
+ */
+export function rollingMean(values: number[], window: number): number[] {
+	const half = Math.floor(window / 2);
+	return values.map((_, i) => {
+		let sum = 0;
+		let count = 0;
+		for (let k = i - half; k <= i + half; k++) {
+			const v = values[k];
+			if (finite(v)) {
+				sum += v;
+				count++;
+			}
+		}
+		return count > 0 ? sum / count : NaN;
+	});
+}
+
+/** Rolling total over the same window (used for precipitation). */
+export function rollingSum(values: number[], window: number): number[] {
+	return rollingMean(values, window).map((v) => (finite(v) ? v * window : NaN));
+}
diff --git a/src/routes/weather/week/[location]/+page.svelte b/src/routes/weather/week/[location]/+page.svelte
index 60000f7..f3324d5 100644
--- a/src/routes/weather/week/[location]/+page.svelte
+++ b/src/routes/weather/week/[location]/+page.svelte
@@ -12,6 +12,8 @@
 		storedVariablePrefs
 	} from '$lib/stores/settings';
 
+	import { buildLocationRoute } from '$lib/utils/location';
+
 	import { ChartContainer } from '$lib/components/charts';
 
 	import {
@@ -76,6 +78,10 @@
 		storedLocation.set(data.location);
 	});
 
+	// Lets the strip's side buttons hand over to the archive / seasonal outlook
+	// for the same place once their range is exhausted.
+	let locationRoute = $derived(buildLocationRoute(location));
+
 	let mounted = $state(false);
 	let loading = $state(true);
 	let loadError = $state<FriendlyWeatherError | null>(null);
@@ -318,6 +324,7 @@
 					onExtend={() => (forecastDays = 15)}
 					canExtendPast={pastDays < 3}
 					onExtendPast={() => (pastDays = 3)}
+					{locationRoute}
 				/>
 			{/if}
 
diff --git a/src/routes/weather/week/[location]/DailyStripSticky.svelte b/src/routes/weather/week/[location]/DailyStripSticky.svelte
index 060ebbb..fcc37c5 100644
--- a/src/routes/weather/week/[location]/DailyStripSticky.svelte
+++ b/src/routes/weather/week/[location]/DailyStripSticky.svelte
@@ -1,6 +1,8 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
 
+	import { resolve } from '$app/paths';
+
 	import { formatZoned, getRelativeDayLabel, isSameDayInZone } from '$lib/utils/date';
 
 	import { getTempStyle } from '../../utils/colors';
@@ -23,6 +25,11 @@
 		onExtend?: () => void;
 		canExtendPast?: boolean;
 		onExtendPast?: () => void;
+		/**
+		 * Location segment for the hand-off links that replace the side buttons
+		 * once their range is exhausted. Omit to leave the slots empty.
+		 */
+		locationRoute?: string;
 	}
 
 	let {
@@ -33,7 +40,8 @@
 		canExtend = false,
 		onExtend,
 		canExtendPast = false,
-		onExtendPast
+		onExtendPast,
+		locationRoute
 	}: Props = $props();
 
 	// ─── Scroll-driven collapse (full cards → compact strip) ────────────────────
@@ -82,10 +90,16 @@
 	let scrolledForRef: FetchedDaily | null = null;
 	$effect(() => {
 		const d = daily;
-		if (!d || !canExtendPast || !stripScrollEl || !daysWrapEl || scrolledForRef === d) return;
+		if (!d || !stripScrollEl || !daysWrapEl || scrolledForRef === d) return;
 		scrolledForRef = d;
 		const scroll = stripScrollEl;
 		const wrap = daysWrapEl;
+		if (!canExtendPast) {
+			// the past button has been replaced by the history link, which is a
+			// destination rather than a control: it stays in view instead of parked
+			scroll.scrollLeft = 0;
+			return;
+		}
 		// the delta form is self-correcting (a no-op once right), so apply after
 		// layout and once more after late-loading CSS/fonts settle — otherwise a
 		// sliver of the past button can stay visible on first paint
@@ -110,7 +124,7 @@
 <div bind:this={sentinelEl} class="sentinel" aria-hidden="true"></div>
 
 <div
-	class="daystrip sticky -top-3 z-30 -mx-3 lg:-top-6 lg:-mx-8"
+	class="daystrip sticky -top-3 z-30 -mx-3 lg:-top-6 lg:-mx-8 mt-1"
 	class:js-snap={needsSnapFallback}
 	class:compact
 	class:stuck
@@ -122,7 +136,7 @@
 				     match the 15-days button on the other end -->
 				<button
 					type="button"
-					class="strip-side flex shrink-0 cursor-pointer flex-col items-center justify-center gap-0.5 rounded-xl border border-dashed border-primary/50 bg-primary/5 text-primary transition-colors hover:border-primary hover:bg-primary/10"
+					class="strip-side strip-park flex shrink-0 cursor-pointer flex-col items-center justify-center gap-0.5 rounded-xl border border-dashed border-primary/50 bg-primary/5 text-primary transition-colors hover:border-primary hover:bg-primary/10"
 					onclick={onExtendPast}
 					aria-label="Load the past 3 days"
 					title="Load the past 3 days"
@@ -141,6 +155,31 @@
 					</span>
 					<span class="text-[9px] leading-tight font-semibold">past</span>
 				</button>
+			{:else if locationRoute}
+				<!-- the past days are already in the strip: the only way further back
+				     is the archive, so the button hands over to it -->
+				<a
+					href={resolve('/weather/historical/[location]', { location: locationRoute })}
+					class="strip-side flex shrink-0 cursor-pointer flex-col items-center justify-center gap-0.5 rounded-xl border border-dashed border-primary/50 bg-primary/5 text-primary transition-colors hover:border-primary hover:bg-primary/10"
+					aria-label="Open the historical weather archive"
+					title="Historical weather: any past date back to 1940"
+				>
+					<svg
+						class="h-4 w-4"
+						fill="none"
+						stroke="currentColor"
+						viewBox="0 0 24 24"
+						stroke-width="2"
+					>
+						<path stroke-linecap="round" stroke-linejoin="round" d="M12 8v4l3 2" />
+						<path
+							stroke-linecap="round"
+							stroke-linejoin="round"
+							d="M3.5 9a9 9 0 1 0 2.2-3.6L3 8m0-4.5V8h4.5"
+						/>
+					</svg>
+					<span class="text-[9px] leading-tight font-semibold">history</span>
+				</a>
 			{/if}
 
 			<div class="strip-days flex" bind:this={daysWrapEl}>
@@ -322,6 +361,27 @@
 						</span>
 						<span class="text-[9px] leading-tight font-semibold">days</span>
 					</button>
+				{:else if locationRoute}
+					<!-- the strip is at the model's limit: anything further out is a
+					     seasonal outlook, so the button hands over to it -->
+					<a
+						href={resolve('/weather/seasonal/[location]', { location: locationRoute })}
+						class="strip-side flex shrink-0 cursor-pointer flex-col items-center justify-center gap-0.5 rounded-xl border border-dashed border-primary/50 bg-primary/5 text-primary transition-colors hover:border-primary hover:bg-primary/10"
+						aria-label="Open the seasonal outlook"
+						title="Seasonal outlook: monthly trends for the months ahead"
+					>
+						<svg
+							class="h-4 w-4"
+							fill="none"
+							stroke="currentColor"
+							viewBox="0 0 24 24"
+							stroke-width="2"
+						>
+							<path stroke-linecap="round" stroke-linejoin="round" d="M3 17l6-6 4 4 7-7" />
+							<path stroke-linecap="round" stroke-linejoin="round" d="M16 8h5v5" />
+						</svg>
+						<span class="text-[9px] leading-tight font-semibold">seasonal</span>
+					</a>
 				{/if}
 			</div>
 		{/if}
@@ -514,7 +574,7 @@
 	   (Browsers too old to register --strip-p simply switch instantly.) */
 	.daystrip.js-snap {
 		transition:
-			--strip-p 0.28s ease,
+			--strip-p 0.32s ease,
 			--stuck 0.15s ease;
 	}
 	.daystrip.js-snap.compact {
@@ -527,7 +587,7 @@
 		/* larger cards need a touch longer to feel smooth */
 		.daystrip.js-snap {
 			transition:
-				--strip-p 0.55s ease,
+				--strip-p 0.42s ease,
 				--stuck 0.15s ease;
 		}
 	}
@@ -549,13 +609,14 @@
 	}
 	/* Scroll containers clip at the PADDING edge, so a parked past button would
 	   always leak a sliver across the row's left padding. Extending the days
-	   group's left edge (only while the past button exists) moves max-scroll so
-	   the button parks fully beyond the clip edge. */
-	.strip-side + .strip-days {
+	   group's left edge (only while the parked past button exists) moves
+	   max-scroll so the button parks fully beyond the clip edge. The history
+	   link that replaces it is never parked, so it keeps the normal gap. */
+	.strip-park + .strip-days {
 		padding-left: calc(12px - var(--gap-min));
 	}
 	@media (min-width: 1024px) {
-		.strip-side + .strip-days {
+		.strip-park + .strip-days {
 			padding-left: calc(32px - var(--gap-min));
 		}
 	}