San Francisco’s warmest months are September and October, with average highs of 70.2 and 69.8 degrees. The wettest are December, January and February.
Those numbers are NOAA’s 1991-2020 normals for the downtown station. Averages hide the city’s fog and microclimates, so check the forecast the week you go.
NOAA data read 27 October 2026. Station: San Francisco downtown (GHCN USW00023272), not the airport.
| Month | Average high (°F) | Average low (°F) | Rain (inches) | Rain at a glance |
|---|---|---|---|---|
| January | 57.8 | 46.6 | 4.40 | |
| February | 60.4 | 47.9 | 4.37 | |
| March | 62.1 | 48.9 | 3.15 | |
| April | 63.0 | 49.7 | 1.60 | |
| May | 64.1 | 51.4 | 0.70 | |
| June | 66.5 | 53.0 | 0.20 | |
| July | 66.3 | 54.4 | 0.01 | |
| August | 67.9 | 55.5 | 0.06 | |
| September | 70.2 | 55.6 | 0.10 | |
| October | 69.8 | 54.4 | 0.94 | |
| November | 63.7 | 50.7 | 2.60 | |
| December | 57.9 | 47.0 | 4.76 |
What the Numbers Mean for a Trip
Even the warmest month averages under 71 degrees at the downtown station, so a layer is part of the plan in any season. June through September are the driest months in the table, each with 0.20 inches or less of normal rain. Rain picks up in November and is heaviest in December through February.
Event timing matters as much as weather. Our events by month hub shows what is on each month, this weekend updates itself, and Rainy Weekend in San Francisco covers indoor plans. For what to pack, read San Francisco Weather: Fog, Microclimates and What to Wear, and the microclimate tracker compares neighborhoods.
What We Could Not Confirm
- NOAA’s table is for the downtown station. We did not find a National Weather Service statement about fog season or microclimates, so we do not state a fog season.
- Normals are 30-year averages. Any single year can run warmer, cooler or wetter.
- The values were read through a page extraction of NOAA’s monthly CSV file, so check the file for exact figures before quoting them.
Questions People Ask
When is the best time to visit San Francisco?
On temperature, September and October have the highest monthly averages in NOAA’s table, and the summer months are the driest. Pick by what you want to see: our events-by-month hub shows each month.
Does it rain in summer?
Normals for June through September are 0.20 inches or less a month.
Sources
- NOAA NCEI, 1991-2020 monthly normals, San Francisco downtown: https://www.ncei.noaa.gov/data/normals-monthly/1991-2020/access/USW00023272.csv (read 27 October 2026)