San Francisco Climate — Average Highs, Lows & Rainfall by Month
San Francisco has a temperate climate with four distinct seasons. Daytime temperatures average 20°C / 69°F in September, the warmest month, and drop to 13°C / 56°F in December, the coldest. Overnight lows in December average 8°C / 46°F. San Francisco receives about 650 mm of rain a year across roughly 59 wet days, with December the wettest month.
Averages for 2021–2025 · Open-Meteo Historical Weather API (ERA5 reanalysis) · Updated 2026-10-05
Monthly averages in San Francisco
Average daytime high, overnight low and rainfall for each month of the year.
| Month | Avg high | Avg low | Rainfall | Wet days |
|---|---|---|---|---|
| January | 14°C / 57°F | 8°C / 46°F | 104 mm | 8 |
| February | 14°C / 58°F | 8°C / 46°F | 89 mm | 9 |
| March | 14°C / 58°F | 9°C / 47°F | 104 mm | 11 |
| April | 16°C / 60°F | 10°C / 49°F | 22 mm | 3 |
| May | 18°C / 64°F | 11°C / 52°F | 12 mm | 2 |
| June | 18°C / 65°F | 12°C / 54°F | 2 mm | 0 |
| July | 18°C / 65°F | 13°C / 55°F | 0 mm | 0 |
| August | 20°C / 68°F | 14°C / 57°F | 1 mm | 0 |
| September | 20°C / 69°F | 14°C / 58°F | 5 mm | 2 |
| October | 20°C / 69°F | 13°C / 55°F | 43 mm | 3 |
| November | 16°C / 61°F | 10°C / 50°F | 78 mm | 8 |
| December | 13°C / 56°F | 8°C / 47°F | 191 mm | 13 |
Best time to visit San Francisco
July, August, June offer the most comfortable weather in San Francisco: mild daytime temperatures with the year's lowest rainfall — July averages 18°C (65°F); August averages 20°C (68°F); June averages 18°C (65°F).
San Francisco climate FAQ
- What is the hottest month in San Francisco?
- September is the hottest month in San Francisco, with average daytime highs of 20°C / 69°F and overnight lows of 14°C / 58°F (averages for 2021–2025).
- What is the coldest month in San Francisco?
- December is the coldest month in San Francisco, with average highs of 13°C / 56°F and lows of 8°C / 47°F.
- How much rain does San Francisco get a year?
- San Francisco receives about 650 mm of rainfall a year, spread over roughly 59 wet days. December is the wettest month (191 mm on average) and July the driest (0 mm).
- When is the best time to visit San Francisco?
- July, August, June are the most comfortable months in San Francisco: mild daytime temperatures with the least rainfall of the year.
Want today's conditions instead of averages?
See live weather in San Francisco →Source: Open-Meteo Historical Weather API (ERA5 reanalysis), Open-Meteo. Averages are daily means across 2021–2025 and are rounded for display — for a live forecast see the San Francisco weather page.