Santa Rosa Weather in September
Average highs run from 26°C on September 1 to 26°C on September 30, and lows from 16°C to 16°C. Normal precipitation for the month is 15 mm over about 3 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
- 26°C
- Average low
- 16°C
- Precipitation
- 15 mm
- Reanalysis high
- 30°CSep 10, 1997
- Reanalysis low
- 12°CSep 4, 2018
- Daylight
- 11 h 54 min to 12 h 11 min
- Cloud cover
- 70%
- Humidity
- 64%
- Dew point
- 13°C
- Wind
- 6.5 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 | 26°C | 16°C | 28°C 2017 | 14°C 2002 | 7% |
| Sep 2 | 26°C | 16°C | 29°C 2008 | 14°C 2002 | 8% |
| Sep 3 | 26°C | 16°C | 28°C 2013 | 14°C 2002 | 9% |
| Sep 4 | 26°C | 16°C | 28°C 2013 | 12°C 2018 | 10% |
| Sep 5 | 26°C | 16°C | 29°C 1997 | 13°C 2018 | 10% |
| Sep 6 | 26°C | 16°C | 30°C 1997 | 13°C 2018 | 10% |
| Sep 7 | 26°C | 16°C | 29°C 1997 | 13°C 2018 | 11% |
| Sep 8 | 26°C | 16°C | 29°C 1997 | 14°C 2008 | 11% |
| Sep 9 | 26°C | 16°C | 30°C 1997 | 13°C 2008 | 12% |
| Sep 10 | 26°C | 16°C | 30°C 1997 | 14°C 1991 | 12% |
| Sep 11 | 26°C | 16°C | 30°C 2016 | 12°C 2003 | 11% |
| Sep 12 | 26°C | 16°C | 29°C 1998 | 13°C 2003 | 11% |
| Sep 13 | 26°C | 16°C | 29°C 2016 | 13°C 2004 | 10% |
| Sep 14 | 26°C | 16°C | 29°C 2016 | 14°C 2004 | 11% |
| Sep 15 | 26°C | 16°C | 30°C 2019 | 14°C 1992 | 12% |
| Sep 16 | 26°C | 16°C | 30°C 2010 | 14°C 1992 | 13% |
| Sep 17 | 26°C | 16°C | 30°C 2010 | 14°C 2008 | 13% |
| Sep 18 | 26°C | 16°C | 29°C 2019 | 14°C 2001 | 13% |
| Sep 19 | 26°C | 16°C | 29°C 2006 | 14°C 1991 | 14% |
| Sep 20 | 26°C | 16°C | 30°C 2017 | 13°C 1991 | 16% |
| Sep 21 | 26°C | 16°C | 29°C 2004 | 13°C 2008 | 16% |
| Sep 22 | 26°C | 16°C | 28°C 2019 | 14°C 1995 | 16% |
| Sep 23 | 26°C | 16°C | 29°C 2013 | 14°C 2008 | 17% |
| Sep 24 | 26°C | 16°C | 28°C 1995 | 14°C 2008 | 16% |
| Sep 25 | 26°C | 16°C | 29°C 2020 | 14°C 1996 | 17% |
| Sep 26 | 26°C | 16°C | 28°C 2014 | 14°C 2013 | 18% |
| Sep 27 | 26°C | 16°C | 29°C 2006 | 14°C 2012 | 19% |
| Sep 28 | 26°C | 16°C | 28°C 2010 | 14°C 2012 | 19% |
| Sep 29 | 26°C | 16°C | 29°C 2016 | 14°C 1992 | 19% |
| Sep 30 | 26°C | 16°C | 29°C 2016 | 14°C 1996 | 20% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT-5).
- September 1
- sunrise 6:03 AM, sunset 5:57 PM
- September 30
- sunrise 5:44 AM, sunset 5:55 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.