Weather in City and County of San Francisco, California for September 2026
Small Craft Advisory - See hour by hour.
Until now, September 2026 in City and County of San Francisco has been nearly identical to the historical average, with a temperature of 20.4 °F (showing only a slight deviation of 0.1 °F).
The forecast for the upcoming days in City and County of San Francisco predicts a temperature of 19.4 °F, which is slightly above the historical average.
In general, the average temperature in City and County of San Francisco at the beginning of September is 21.4 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 17.9 °F by the end of September.
Precipitation in City and County of San Francisco during September is a rare event, with an average of fewer than 2 rainy days.
New! Chat with our AI weatherman - it’s amazing and free.
Official Weather Alert ⚠️
Temperatures
Rain 🌧️
More
City and County of San Francisco Weather September
Temperatures trend during September in City and County of San Francisco
September weather in City and County of San Francisco day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Patchy rain possible | 20° /12° | 0.7 mm | 4 | |
| Sept. 2 |  Sunny | 19° /13° | 0 mm | 6 | |
| Sept. 3 | Sunny | 22° /13° | 1.8 mm | 5 | |
| Sept. 4 | Sunny | 22° /13° | 0.1 mm | 6 | |
| Sept. 5 | Sunny | 23° /14° | 0 mm | 7 | |
| Sept. 6 | Sunny | 22° /13° | 0 mm | 6 | |
| Sept. 7 | Sunny | 22° /13° | 0 mm | 6 | |
| Sept. 8 | Sunny | 23° /13° | 0 mm | 6 | |
| Sept. 9 | Sunny | 23° /14° | 0 mm | 5 | |
| Sept. 10 |  Partly cloudy | 19° /13° | 0 mm | 5 | |
| Sept. 11 | Sunny | 20° /13° | 0.1 mm | 6 | |
| Sept. 12 | Sunny | 20° /13° | 0 mm | 6 | |
| Sept. 13 | Sunny | 20° /12° | 0 mm | 6 | |
| Sept. 14 | Sunny | 21° /13° | 0 mm | 5 | |
| Sept. 15 | Sunny | 20° /13° | 0 mm | 6 | |
| Sept. 16 | Partly cloudy | 19° /12° | 0.1 mm | 5 | |
| Sept. 17 |  Mist | 19° /12° | 0.4 mm | 5 | |
| Sept. 18 |  Moderate or heavy rain shower | 18° /12° | 7.1 mm | 5 | |
| Sept. 19 |  Overcast | 18° /13° | 0.2 mm | 4 | |
| Sept. 20 | Overcast | 20° /12° | 0.1 mm | 4 | |
| Sept. 21 | Patchy rain possible | 16° /15° | 0.4 mm | 6.1 | |
| Sept. 22 | Sunny | 17° /14° | 0.1 mm | 6.5 | |
| Sept. 23 | Sunny | 19° /14° | 0 mm | 6.6 | |
| Sept. 24 | Sunny | 17° /15° | 0 mm | 6.3 | |
| Sept. 25 | Sunny | 17° /14° | 0 mm | 6.2 | |
| Sept. 26 | Overcast | 17° /14° | 0 mm | 5 | |
| Sept. 27 | Sunny | 17° /13° | 0 mm | 5 | |
| Sept. 28 | Sunny | 17° /14° | 0 mm | 5 | |
| Sept. 29 | Sunny | 19° /15° | 0 mm | 5 | |
| Sept. 30 | Sunny | 21° /15° | 0 mm | 6 | |
| Next | |||||
City and County of San Francisco in September - FAQ
What are the expected maximum and minimum temperatures in City and County of San Francisco during September?
How much rainfall should be expected in City and County of San Francisco during September?
What are the typical wind conditions in City and County of San Francisco during September?
September rainfall patterns in City and County of San Francisco
UV exposure in City and County of San Francisco during September
Quick links
Where is City and County of San Francisco?Get accurate weather forecasts for City and County of San Francisco, located at latitude 37.775 and longitude -122.419. Stay updated with localized weather information tailored for City and County of San Francisco.