San Francisco Weather in September
Average highs run from 31°C on September 1 to 29°C on September 30, and lows from 24°C to 23°C. Normal precipitation for the month is 219 mm over about 24 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
- 30°C
- Average low
- 24°C
- Precipitation
- 219 mm
- Reanalysis high
- 38°CSep 12, 1994
- Reanalysis low
- 21°CSep 13, 2007
- Daylight
- 12 h 23 min to 12 h 01 min
- Cloud cover
- 72%
- Humidity
- 81%
- Dew point
- 22°C
- Wind
- 8.3 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 | 31°C | 24°C | 35°C 2015 | 22°C 2012 | 79% |
| Sep 2 | 31°C | 24°C | 37°C 1994 | 23°C 1999 | 79% |
| Sep 3 | 31°C | 24°C | 37°C 1994 | 22°C 1999 | 77% |
| Sep 4 | 30°C | 24°C | 37°C 1994 | 22°C 2007 | 77% |
| Sep 5 | 30°C | 24°C | 35°C 1994 | 22°C 2014 | 77% |
| Sep 6 | 30°C | 24°C | 38°C 1994 | 22°C 2014 | 77% |
| Sep 7 | 30°C | 24°C | 38°C 1994 | 22°C 2014 | 78% |
| Sep 8 | 30°C | 24°C | 37°C 1994 | 22°C 2013 | 78% |
| Sep 9 | 30°C | 24°C | 37°C 1994 | 22°C 1993 | 79% |
| Sep 10 | 30°C | 24°C | 37°C 1994 | 23°C 2012 | 80% |
| Sep 11 | 30°C | 24°C | 38°C 1994 | 22°C 1999 | 79% |
| Sep 12 | 30°C | 24°C | 38°C 1994 | 21°C 2012 | 79% |
| Sep 13 | 30°C | 24°C | 36°C 1994 | 21°C 2007 | 79% |
| Sep 14 | 30°C | 24°C | 35°C 2019 | 22°C 2007 | 78% |
| Sep 15 | 30°C | 24°C | 36°C 1991 | 22°C 2007 | 79% |
| Sep 16 | 30°C | 24°C | 36°C 1994 | 22°C 2007 | 80% |
| Sep 17 | 30°C | 24°C | 37°C 1994 | 22°C 2001 | 80% |
| Sep 18 | 30°C | 24°C | 34°C 1996 | 22°C 1995 | 82% |
| Sep 19 | 30°C | 24°C | 34°C 1994 | 22°C 1995 | 84% |
| Sep 20 | 30°C | 24°C | 35°C 1996 | 22°C 2011 | 85% |
| Sep 21 | 29°C | 24°C | 35°C 1996 | 22°C 2011 | 85% |
| Sep 22 | 29°C | 24°C | 34°C 1994 | 22°C 2016 | 85% |
| Sep 23 | 29°C | 24°C | 36°C 1994 | 23°C 1992 | 86% |
| Sep 24 | 29°C | 23°C | 34°C 1993 | 22°C 1995 | 85% |
| Sep 25 | 29°C | 23°C | 35°C 1996 | 22°C 1991 | 85% |
| Sep 26 | 29°C | 23°C | 35°C 1996 | 22°C 2009 | 85% |
| Sep 27 | 29°C | 23°C | 32°C 2006 | 21°C 2009 | 84% |
| Sep 28 | 29°C | 23°C | 32°C 2009 | 22°C 1999 | 82% |
| Sep 29 | 29°C | 23°C | 34°C 1991 | 22°C 1999 | 81% |
| Sep 30 | 29°C | 23°C | 34°C 1991 | 22°C 2010 | 81% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (CST).
- September 1
- sunrise 5:41 AM, sunset 6:04 PM
- September 30
- sunrise 5:42 AM, sunset 5:43 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 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.