San Francisco Weather in September
Average highs run from 23°C on September 1 to 25°C on September 30, and lows from 8°C to 11°C. Normal precipitation for the month is 42 mm over about 6 wet days.
September day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
September at a glance
- Average high
- 24°C
- Average low
- 9°C
- Precipitation
- 42 mm
- Reanalysis high
- 40°CSep 23, 1994
- Reanalysis low
- 0°CSep 12, 2005
- Daylight
- 11 h 27 min to 12 h 23 min
- Cloud cover
- 50%
- Humidity
- 62%
- Dew point
- 7°C
- Wind
- 15.8 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 23°C | 8°C | 35°C 2004 | 0°C 2002 | 17% |
| Sep 2 | 23°C | 8°C | 29°C 2014 | 0°C 2005 | 18% |
| Sep 3 | 23°C | 8°C | 31°C 2004 | 1°C 2019 | 18% |
| Sep 4 | 23°C | 8°C | 37°C 2004 | 1°C 2006 | 18% |
| Sep 5 | 23°C | 8°C | 37°C 1995 | 1°C 2006 | 18% |
| Sep 6 | 23°C | 8°C | 38°C 1995 | 3°C 1996 | 19% |
| Sep 7 | 23°C | 8°C | 35°C 2013 | 1°C 2016 | 19% |
| Sep 8 | 23°C | 8°C | 30°C 2007 | 2°C 1994 | 18% |
| Sep 9 | 23°C | 9°C | 38°C 2013 | 2°C 1996 | 16% |
| Sep 10 | 23°C | 9°C | 38°C 2013 | 2°C 2003 | 16% |
| Sep 11 | 23°C | 9°C | 39°C 2013 | 2°C 2015 | 16% |
| Sep 12 | 24°C | 9°C | 31°C 1994 | 0°C 2005 | 16% |
| Sep 13 | 24°C | 9°C | 31°C 1996 | 1°C 2005 | 14% |
| Sep 14 | 24°C | 9°C | 29°C 2012 | 4°C 2003 | 15% |
| Sep 15 | 24°C | 9°C | 32°C 2012 | 4°C 2005 | 14% |
| Sep 16 | 24°C | 9°C | 33°C 2011 | 2°C 2001 | 14% |
| Sep 17 | 24°C | 9°C | 33°C 1995 | 2°C 2013 | 14% |
| Sep 18 | 24°C | 9°C | 38°C 1994 | 3°C 1998 | 14% |
| Sep 19 | 24°C | 9°C | 40°C 1994 | 1°C 1998 | 14% |
| Sep 20 | 24°C | 9°C | 37°C 1996 | 1°C 1998 | 15% |
| Sep 21 | 25°C | 9°C | 33°C 1999 | 2°C 1998 | 16% |
| Sep 22 | 25°C | 10°C | 38°C 2018 | 6°C 2013 | 16% |
| Sep 23 | 25°C | 10°C | 40°C 1994 | 3°C 2013 | 19% |
| Sep 24 | 25°C | 10°C | 34°C 2020 | 2°C 2007 | 21% |
| Sep 25 | 25°C | 10°C | 34°C 2020 | 3°C 2007 | 22% |
| Sep 26 | 25°C | 10°C | 35°C 2006 | 2°C 2012 | 24% |
| Sep 27 | 25°C | 10°C | 33°C 2004 | 4°C 2012 | 25% |
| Sep 28 | 25°C | 10°C | 35°C 2011 | 3°C 2009 | 26% |
| Sep 29 | 25°C | 10°C | 35°C 2019 | 3°C 2009 | 26% |
| Sep 30 | 25°C | 11°C | 38°C 2020 | 3°C 2009 | 26% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT-3).
- September 1
- sunrise 7:25 AM, sunset 6:52 PM
- September 30
- sunrise 6:47 AM, sunset 7:10 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.