Walnut Weather in September
Average highs run from 92°F on September 1 to 84°F on September 30, and lows from 62°F to 58°F. Normal precipitation for the month is 0.01 in over about 0 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
- 89°F
- Average low
- 60°F
- Precipitation
- 0.01 in
- Record high
- 113°FSep 10, 1948
- Record low
- 38°FSep 26, 1948
- Chance of a freeze
- 0%
- Days of 90°F or more
- 15.3
- Daylight
- 12 h 52 min to 11 h 52 min
- Cloud cover
- 16%
- Humidity
- 50%
- Dew point
- 50°F
- Wind
- 5.4 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 | 92°F | 62°F | 110°F 1955 | 43°F 1941 | 1% |
| Sep 2 | 92°F | 62°F | 110°F 1955 | 43°F 1914 | 1% |
| Sep 3 | 92°F | 62°F | 109°F 1955 | 44°F 1921 | 1% |
| Sep 4 | 92°F | 62°F | 107°F 1955 | 45°F 1925 | 1% |
| Sep 5 | 91°F | 62°F | 109°F 1955 | 41°F 1919 | 1% |
| Sep 6 | 91°F | 62°F | 112°F 1955 | 42°F 1933 | 1% |
| Sep 7 | 91°F | 62°F | 110°F 1949 | 42°F 1933 | 1% |
| Sep 8 | 91°F | 62°F | 110°F 1984 | 43°F 1914 | 1% |
| Sep 9 | 91°F | 62°F | 105°F 1956 | 42°F 1900 | 1% |
| Sep 10 | 90°F | 62°F | 113°F 1948 | 43°F 1920 | 1% |
| Sep 11 | 90°F | 61°F | 107°F 1898 | 43°F 1919 | 1% |
| Sep 12 | 90°F | 61°F | 105°F 1898 | 42°F 1952 | 1% |
| Sep 13 | 90°F | 61°F | 108°F 1938 | 43°F 1916 | 1% |
| Sep 14 | 89°F | 61°F | 107°F 1971 | 42°F 1939 | 1% |
| Sep 15 | 89°F | 61°F | 106°F 1937 | 43°F 1914 | 1% |
| Sep 16 | 89°F | 61°F | 108°F 1922 | 42°F 1921 | 2% |
| Sep 17 | 89°F | 60°F | 110°F 1922 | 42°F 1919 | 2% |
| Sep 18 | 88°F | 60°F | 106°F 1939 | 41°F 1933 | 2% |
| Sep 19 | 88°F | 60°F | 106°F 1899 | 40°F 1925 | 2% |
| Sep 20 | 88°F | 60°F | 108°F 1939 | 41°F 1925 | 2% |
| Sep 21 | 87°F | 60°F | 106°F 1939 | 41°F 1924 | 2% |
| Sep 22 | 87°F | 59°F | 109°F 1989 | 42°F 1924 | 2% |
| Sep 23 | 87°F | 59°F | 110°F 1949 | 39°F 1941 | 3% |
| Sep 24 | 86°F | 59°F | 106°F 1978 | 41°F 1923 | 3% |
| Sep 25 | 86°F | 59°F | 108°F 1963 | 41°F 1934 | 3% |
| Sep 26 | 86°F | 59°F | 109°F 1978 | 38°F 1948 | 3% |
| Sep 27 | 85°F | 58°F | 111°F 2010 | 39°F 1948 | 4% |
| Sep 28 | 85°F | 58°F | 107°F 1963 | 40°F 1934 | 4% |
| Sep 29 | 85°F | 58°F | 105°F 1963 | 42°F 1913 | 4% |
| Sep 30 | 84°F | 58°F | 104°F 1980 | 41°F 1925 | 5% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:25 AM, sunset 7:17 PM
- September 30
- sunrise 6:45 AM, sunset 6:37 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00047050 (Pomona/fairplex), public domain. Records: NOAA GHCN-Daily, station USC00047050, 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.