WeatherArchive / Climate averages / San Francisco
San Francisco climate: average weather by month
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.