San Francisco County Climate
San Francisco County, California
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
56.9°F
Annual Precip
21.8"
Annual Snowfall
0.0"
Extreme Heat Days
2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
10b
Minimum winter temperature range for plant survival
2,588
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: San Francisco County
Climate Verdict
San Francisco County has a mild, with an average annual temperature of 56.9°F, semi-arid conditions with only 21.8 inches of annual precipitation, rare extreme heat with only 2 days above 90°F annually, virtually no measurable snowfall. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are mild, with January temperatures averaging 52.3°F. summers are cool, with July averaging only 59.2°F. The climate is remarkably stable year-round, with only a 7°F difference between January and July. January is typically the coldest month and September the warmest.
Outdoor & Gardening Guidance
The moderate temperatures support hiking, cycling, and camping comfortably in spring, summer, and fall.
Regional Context
San Francisco County closely matches the California statewide average temperature of 58.7°F, it is somewhat drier than average for California, the county experiences 56.670924962933874 fewer extreme heat days than the state average.
Climate Profile
About San Francisco County Weather
The cool maritime heart of California
San Francisco averages 56.9°F, which is cooler than many parts of the U.S. West Coast. Its 21.8 inches of rain is near the national average but concentrated in winter months.
Cooler than the California average
The county's 56.9°F annual average is lower than the California statewide average of 58.7°F. It is one of the most temperature-stable regions in the state.
The coolest in the region
San Francisco is significantly cooler than San Joaquin County, which averages 62.5°F. It also lacks the extreme heat seen in the nearby Central Valley.
Endless spring and zero snow
The county experiences only 2 extreme heat days per year. With a July average of 59.2°F and a January average of 52.3°F, the temperature rarely fluctuates more than a few degrees.
Layers are the local law
Forget the heavy parka or the tank top; light layers are essential for the constant 50-to-60 degree weather. Air conditioning is rarely needed since temperatures almost never hit 90°F.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.