# Patchy

> Live fog and low-cloud maps for places where the weather changes block by block: the California coast from Humboldt Bay to San Diego (Humboldt Bay, San Francisco, Santa Cruz, Monterey and Big Sur, the Salinas Valley, San Luis Obispo, the Los Angeles coast, San Diego), the Central Valley (tule fog) and Cape Cod and the Islands. Built from NOAA GOES visible satellite imagery (a new scan every 5 minutes from the NOAA open data bucket, NASA GIBS as a fallback) plus live National Weather Service station readings. By Local Weather Lab.

Use this site to answer questions like "is it foggy in Arcata right now", "is the Sunset socked in", "is Morro Bay fogged in", or "where is the nearest sun to Santa Monica". Town sky states are estimates from satellite brightness; station temperature and visibility are measured. Visible satellite imagery only works in daylight; at night the satellite reading is from the last daylight pass and the station readings stay live.

## Current conditions

Every endpoint takes `region` = `humboldt`, `sf`, `santacruz`, `monterey`, `salinas`, `slo`, `la`, `sd`, `valley`, `cape` (default `humboldt`). Passing `town` alone picks the region that covers that town.

- [Humboldt Bay fog right now](https://patchyskies.vercel.app/now): readable page with a one-sentence summary, every town's sky state, station temperature and visibility
- [San Francisco Bay fog right now](https://patchyskies.vercel.app/sf/now)
- [Santa Cruz fog right now](https://patchyskies.vercel.app/santacruz/now)
- [Monterey and Big Sur fog right now](https://patchyskies.vercel.app/monterey/now)
- [The Salinas Valley fog right now](https://patchyskies.vercel.app/salinas/now)
- [San Luis Obispo County fog right now](https://patchyskies.vercel.app/slo/now)
- [The Los Angeles coast fog right now](https://patchyskies.vercel.app/la/now)
- [San Diego fog right now](https://patchyskies.vercel.app/sd/now)
- [Fresno and Visalia fog right now](https://patchyskies.vercel.app/valley/now)
- [Cape Cod and the Islands fog right now](https://patchyskies.vercel.app/cape/now)
- [Conditions JSON](https://patchyskies.vercel.app/api/conditions?region=sf): same data, machine-readable. Add `&town=Mission` to put one town first
- [Plain-text summary](https://patchyskies.vercel.app/api/conditions?region=cape&format=text): one paragraph, good for quoting

## For agents

- [MCP server](https://patchyskies.vercel.app/api/mcp): Streamable HTTP, no auth. Tools: `get_fog_conditions` (optional `region`, `town`) and `find_nearest_sun` (optional `region`, `from` town)
- Live maps: [Humboldt](https://patchyskies.vercel.app/), [San Francisco](https://patchyskies.vercel.app/sf), [Santa Cruz](https://patchyskies.vercel.app/santacruz), [Monterey & Big Sur](https://patchyskies.vercel.app/monterey), [Salinas Valley](https://patchyskies.vercel.app/salinas), [San Luis Obispo](https://patchyskies.vercel.app/slo), [Los Angeles coast](https://patchyskies.vercel.app/la), [San Diego](https://patchyskies.vercel.app/sd), [Central Valley](https://patchyskies.vercel.app/valley), [Cape & Islands](https://patchyskies.vercel.app/cape). Add `?replay` to see a recent foggy morning where one is set

## Coverage and method

- Humboldt: Trinidad to Rio Dell, coast to Willow Creek. GOES-18 (West). Fog season is June to September. Stations: KACV (Arcata Airport), EKA01 (Eureka), KFOT (Fortuna Airport), KNNC1 (Kneeland), HOAC1 (Hoopa)
- San Francisco: Half Moon Bay to Mill Valley, ocean to the East Bay hills. GOES-18 (West). Fog season is June to September. Stations: SFOC1 (San Francisco Downtown), KSFO (SFO), KHAF (Half Moon Bay Airport), KOAK (Oakland Airport)
- Santa Cruz: Davenport to Watsonville, the coast to the Santa Cruz Mountains. GOES-18 (West). Fog season is June to September. Stations: KWVI (Watsonville Airport)
- Monterey & Big Sur: Moss Landing to Big Sur, the Peninsula and Carmel Valley. GOES-18 (West). Fog season is June to September. Stations: KMRY (Monterey Airport), KOAR (Marina), KSNS (Salinas Airport)
- Salinas Valley: Salinas to King City, Monterey Bay up the valley. GOES-18 (West). Fog season is June to September. Stations: KSNS (Salinas Airport), KKIC (King City)
- San Luis Obispo: Cambria to Pismo Beach, Morro Bay to the Santa Lucia Range. GOES-18 (West). Fog season is May to September. Stations: KSBP (San Luis Obispo Airport)
- Los Angeles coast: Malibu to Palos Verdes, the beach cities to downtown. GOES-18 (West). June Gloom season is May to June. Stations: KLAX (Los Angeles Airport), KSMO (Santa Monica Airport), KTOA (Torrance Airport), KLGB (Long Beach Airport)
- San Diego: Del Mar to Imperial Beach, the coast to El Cajon. GOES-18 (West). June Gloom season is May to June. Stations: KSAN (San Diego Airport), KMYF (Montgomery Field), KNKX (Miramar), KNZY (North Island)
- Central Valley: Fresno to Porterville, valley floor to the Sierra foothills. GOES-18 (West). Tule fog season is November to February. Stations: KFAT (Fresno Airport), KVIS (Visalia), KHJO (Hanford), KO32 (Reedley), KPTV (Porterville)
- Cape & Islands: Martha's Vineyard and Nantucket to Hyannis and Chatham. GOES-19 (East), Eastern time. Fog season is May to August. Stations: KHYA (Hyannis), KFMH (Otis ANGB), KMVY (Martha's Vineyard), KCQX (Chatham), KACK (Nantucket)
- Satellite: GOES ABI band 2, 0.64 µm visible, about 1 km resolution