San José Weather in September
Average highs run from 30°C on September 1 to 29°C on September 30, and lows from 24°C to 24°C. Normal precipitation for the month is 213 mm over about 23 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
- 29°C
- Average low
- 24°C
- Precipitation
- 213 mm
- Reanalysis high
- 35°CSep 17, 1994
- Reanalysis low
- 22°CSep 18, 1995
- Daylight
- 12 h 19 min to 12 h 02 min
- Cloud cover
- 79%
- Humidity
- 85%
- Dew point
- 23°C
- Wind
- 5.4 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 | 30°C | 24°C | 35°C 1997 | 22°C 2013 | 70% |
| Sep 2 | 30°C | 24°C | 34°C 1997 | 22°C 2010 | 70% |
| Sep 3 | 30°C | 24°C | 34°C 1996 | 23°C 1996 | 69% |
| Sep 4 | 30°C | 24°C | 34°C 1991 | 23°C 2001 | 70% |
| Sep 5 | 30°C | 24°C | 33°C 2004 | 23°C 1993 | 70% |
| Sep 6 | 30°C | 24°C | 35°C 1994 | 22°C 1993 | 72% |
| Sep 7 | 30°C | 24°C | 34°C 1992 | 23°C 1992 | 72% |
| Sep 8 | 30°C | 24°C | 34°C 1994 | 23°C 2020 | 73% |
| Sep 9 | 30°C | 24°C | 35°C 1997 | 23°C 2004 | 74% |
| Sep 10 | 30°C | 24°C | 34°C 1997 | 23°C 2000 | 74% |
| Sep 11 | 30°C | 24°C | 33°C 1994 | 23°C 2001 | 74% |
| Sep 12 | 30°C | 24°C | 33°C 2009 | 23°C 1999 | 73% |
| Sep 13 | 30°C | 24°C | 33°C 1996 | 23°C 1995 | 73% |
| Sep 14 | 30°C | 24°C | 35°C 1996 | 23°C 1994 | 73% |
| Sep 15 | 29°C | 24°C | 35°C 2009 | 23°C 2007 | 75% |
| Sep 16 | 29°C | 24°C | 34°C 1997 | 22°C 2007 | 76% |
| Sep 17 | 29°C | 24°C | 35°C 1994 | 22°C 1992 | 77% |
| Sep 18 | 29°C | 24°C | 33°C 1996 | 22°C 1995 | 78% |
| Sep 19 | 29°C | 24°C | 33°C 2003 | 23°C 1992 | 78% |
| Sep 20 | 29°C | 24°C | 33°C 1997 | 23°C 1999 | 78% |
| Sep 21 | 29°C | 24°C | 34°C 1996 | 23°C 2006 | 77% |
| Sep 22 | 29°C | 24°C | 32°C 1997 | 22°C 2016 | 78% |
| Sep 23 | 29°C | 24°C | 34°C 2003 | 22°C 1999 | 78% |
| Sep 24 | 29°C | 24°C | 31°C 1994 | 22°C 1993 | 78% |
| Sep 25 | 29°C | 24°C | 33°C 1997 | 22°C 1993 | 80% |
| Sep 26 | 29°C | 24°C | 35°C 2003 | 23°C 1993 | 80% |
| Sep 27 | 29°C | 24°C | 32°C 1991 | 23°C 2018 | 80% |
| Sep 28 | 29°C | 24°C | 32°C 1996 | 22°C 1999 | 79% |
| Sep 29 | 29°C | 24°C | 33°C 1996 | 22°C 1999 | 78% |
| Sep 30 | 29°C | 24°C | 32°C 2003 | 22°C 2000 | 76% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (CST).
- September 1
- sunrise 5:31 AM, sunset 5:50 PM
- September 30
- sunrise 5:29 AM, sunset 5:31 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 2026-09-26. Sun and moon: computed with the NOAA solar equations and Meeus.