Riverside County Weather in September
Average highs run from 105°F on September 1 to 97°F on September 30, and lows from 72°F to 63°F. Normal precipitation for the month is 0.32 in over about 1 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 102°F
- Average low
- 68°F
- Precipitation
- 0.32 in
- Record high
- 123°FSep 1, 1950
- Record low
- 48°FSep 25, 1993
- Chance of a freeze
- 0%
- Days of 90°F or more
- 29.0
- Daylight
- 12 h 51 min to 11 h 51 min
- Cloud cover
- 21%
- Humidity
- 31%
- Dew point
- 44°F
- Wind
- 6.7 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 105°F | 72°F | 123°F 1950 | 53°F 1999 | 4% |
| Sep 2 | 105°F | 72°F | 121°F 1982 | 61°F 1999 | 4% |
| Sep 3 | 105°F | 72°F | 116°F 2010 | 59°F 1964 | 4% |
| Sep 4 | 105°F | 72°F | 116°F 2020 | 61°F 2004 | 4% |
| Sep 5 | 104°F | 71°F | 122°F 2020 | 57°F 2004 | 4% |
| Sep 6 | 104°F | 71°F | 117°F 2020 | 58°F 1992 | 4% |
| Sep 7 | 104°F | 71°F | 115°F 2018 | 59°F 1961 | 4% |
| Sep 8 | 104°F | 71°F | 118°F 2018 | 58°F 1987 | 4% |
| Sep 9 | 104°F | 70°F | 117°F 1993 | 55°F 1961 | 4% |
| Sep 10 | 103°F | 70°F | 115°F 1990 | 54°F 2006 | 4% |
| Sep 11 | 103°F | 70°F | 119°F 1990 | 56°F 2010 | 4% |
| Sep 12 | 103°F | 70°F | 118°F 1971 | 54°F 1985 | 4% |
| Sep 13 | 103°F | 69°F | 114°F 1995 | 53°F 1985 | 4% |
| Sep 14 | 102°F | 69°F | 113°F 1951 | 57°F 1985 | 4% |
| Sep 15 | 102°F | 69°F | 113°F 2000 | 51°F 1994 | 4% |
| Sep 16 | 102°F | 68°F | 114°F 2020 | 52°F 1994 | 4% |
| Sep 17 | 101°F | 68°F | 113°F 2020 | 56°F 2006 | 4% |
| Sep 18 | 101°F | 68°F | 114°F 1956 | 51°F 2006 | 4% |
| Sep 19 | 101°F | 67°F | 110°F 1962 | 49°F 1985 | 4% |
| Sep 20 | 100°F | 67°F | 110°F 1987 | 53°F 1971 | 3% |
| Sep 21 | 100°F | 67°F | 110°F 2003 | 54°F 2006 | 3% |
| Sep 22 | 100°F | 66°F | 112°F 1966 | 55°F 1978 | 3% |
| Sep 23 | 99°F | 66°F | 111°F 1966 | 53°F 2004 | 3% |
| Sep 24 | 99°F | 66°F | 109°F 2024 | 50°F 2006 | 3% |
| Sep 25 | 99°F | 65°F | 111°F 1963 | 48°F 1993 | 3% |
| Sep 26 | 98°F | 65°F | 111°F 2010 | 56°F 1986 | 3% |
| Sep 27 | 98°F | 65°F | 112°F 2018 | 55°F 1993 | 3% |
| Sep 28 | 98°F | 64°F | 110°F 1963 | 52°F 2013 | 3% |
| Sep 29 | 97°F | 64°F | 112°F 1980 | 52°F 2013 | 3% |
| Sep 30 | 97°F | 63°F | 112°F 2020 | 50°F 1999 | 3% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:18 AM, sunset 7:09 PM
- September 30
- sunrise 6:38 AM, sunset 6:29 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00003104 (Desert Resorts Rgnl AP), public domain. Records: NOAA GHCN-Daily, station USW00003104, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: 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.