WeatherArchive / Climate averages / San Francisco
San Francisco weather by month: climate averages
San Francisco averages 57°F (14°C) over the year. September is warmest, with highs around 72°F (22°C); January is coldest, with lows near 44°F (7°C). About 20 inches (515 mm) of precipitation falls on roughly 56 days a year, from 30 years of ERA5 data (1996–2025).
| Month | Avg high | Avg low | Precip. | Days ≥1 mm | Sunshine / day |
|---|---|---|---|---|---|
| January | 13.6°C | 6.7°C | 96.0 mm | 9.1 | 7.2 h |
| February | 14.4°C | 7.3°C | 98.9 mm | 9.1 | 8.4 h |
| March | 15.5°C | 8.3°C | 72.6 mm | 8.7 | 9.8 h |
| April | 16.6°C | 9.1°C | 35.6 mm | 4.6 | 11.5 h |
| May | 18.3°C | 10.7°C | 17.5 mm | 2.9 | 12.8 h |
| June | 20.2°C | 12.0°C | 2.7 mm | 0.6 | 13.4 h |
| July | 20.5°C | 12.8°C | 0.5 mm | 0.2 | 13.4 h |
| August | 21.2°C | 13.5°C | 1.1 mm | 0.2 | 12.6 h |
| September | 22.0°C | 13.5°C | 2.6 mm | 0.8 | 11.6 h |
| October | 20.5°C | 12.1°C | 25.9 mm | 3.1 | 9.9 h |
| November | 16.4°C | 9.2°C | 55.1 mm | 6.6 | 8.4 h |
| December | 13.5°C | 7.0°C | 106.0 mm | 9.9 | 6.9 h |
Record high 1996–2025: 38.5°C on 2017-09-02. Record low: -2.3°C on 1998-12-21.
Source: Open-Meteo Historical Weather API (CC BY 4.0). Values are ERA5 reanalysis model data on a ~9–25 km grid, not readings from a weather station, so a single town’s thermometer can differ by a few degrees and local showers can be missed. Grid cell 37.79, -122.41 at 18 m. For snowfall, humidity and a best-time-to-visit score, open San Francisco in the climate tool.
San Francisco weather month by month
The wettest month in San Francisco is December, averaging 4.2 in (106 mm); the driest is July at 0.0 in (1 mm). December has the most days with at least 1 mm of rain (about 10). June is the sunniest month, with about 13.4 hours of sunshine a day, against 6.9 hours in December. If you like average highs between 64 °F and 82 °F (18–28 °C) with few rainy days, aim for June, July and August.
Planning a particular day? See how often that date was wet or hot over 30 years with the event weather odds, or look up what the weather actually was on any past date in the historical weather archive.
Questions people ask
What is the warmest month in San Francisco?
September, with an average daily high of 72°F (22°C) over 1996–2025.
What is the coldest month in San Francisco?
January, when nights average about 44°F (7°C).
What is the rainiest month in San Francisco?
December has the most precipitation (about 4.2 in (106 mm)), and December has the most rainy days (about 10 days with 1 mm or more). The driest month is July.
How much sunshine does San Francisco get?
About 10.5 hours of bright sunshine a day averaged over the year, from 6.9 h in December to 13.4 h in June. Sunshine here is the model’s estimate of hours with direct sun, not hours of daylight.
What is the best month to visit San Francisco for mild weather?
By average high between 64 °F and 82 °F (18–28 °C) and the fewest rainy days: June, July, August. Prices, crowds and events are not included.