How SF Microclimate works

San Francisco can be 60° at Ocean Beach and 80° in the Mission at the same moment. This map shows where it's warm and where it's cool, neighborhood by neighborhood, hour by hour, for the next two days.

Reading the colours

Colour is temperature. Blues and purples are cool, pale yellow is mild, and oranges and reds are warm.

• The thin lines are 2° steps. Some are labelled, like 72°F.
• The card at the top left shows the time you're looking at and the coolest-to-warmest range across the map.
• The map is in 3D, so hills like Twin Peaks and San Bruno Mountain stand up. Temperature is drawn right on the hills.

Moving through time

• Drag the slider at the bottom to move through the next 48 hours, one hour per step.
• Press play to watch the day unfold: morning cool, afternoon warmth, evening fog-cooled west side. Press it again to pause.
• On a computer, click the slider and use the ← → keys for one hour at a time.
• The map opens at the hour closest to now.

Your neighborhoods

Neighborhood names show each neighborhood's average temperature for the hour you're looking at, like GLEN PARK 73°.

• Tap Neighborhoods in the card to choose which ones are labelled.
• Type in the search box (for example noe), then tick the ones you care about. Each row also shows its temperature right now.
• Reset to defaults brings back the starting set; Clear all removes every label.
• Your choice is remembered on this device and browser.

Fog

Tick Fog in the card to show the fog forecast as a soft white layer. The thicker the white, the more likely fog or low cloud is at that hour.

• Move the slider to watch fog roll in at night and burn off in the morning. Hills that rise above the fog, like Twin Peaks, stay clear.
• Neighborhood labels add the chance of fog when it's 20% or more, like SUNSET 57° · fog 100%.
• The dashed white outline is where the GOES-West weather satellite actually saw fog, at the hour of its latest picture. The card says when that picture was taken. Right around sunrise and sunset the satellite can't tell fog from clear ground, so there's no outline then.

Weather stations (real readings)

The round dots are real weather stations: official ones and neighbours' home weather stations. Each shows the temperature it actually measured.

• Tap a dot to compare what the station observed with what this map predicted and with the raw national forecast model (Raw HRRR).
• Dots are bright only at the hour they were measured and faded at other hours.
• Turn them off or on with Stations (observed).

Moving the map

Street names appear once you zoom in close.

Sharing and saving

• Share the link to send someone the map. Add ?h=10 to the end to open at a specific hour (10 hours after the forecast began).
• On iPhone, tap Share, then Add to Home Screen to open it like an app.

How good is the forecast?

The map starts from the U.S. government's high-resolution weather model (NOAA HRRR), which sees San Francisco in blocks about 2 miles wide, and sharpens it with detailed terrain. It's still being tuned. The next version learns from years of local station readings how fog and ocean air push into each neighborhood. Until then, treat neighborhood temperatures as a good guide, typically within a few degrees.

Coming soon

• When the fog will burn off near you.
• Wind.
• A "where to go" list of the warmest, sunniest, least windy spots.

Where the data comes from

• Forecast: NOAA High-Resolution Rapid Refresh (HRRR).
• Fog from space: NOAA GOES-West (GOES-18) satellite.
• Stations: NOAA MADIS, including the Citizen Weather Observer Program, MesoWest and NOAA tide stations.
• Terrain: USGS 3DEP. Neighborhood boundaries: DataSF (public domain).
• Base map: © OpenStreetMap contributors, OpenMapTiles, via OpenFreeMap.

A free, independent project. Not affiliated with or endorsed by NOAA or the National Weather Service.