Prosser Weather in September
Average highs run from 85°F on September 1 to 74°F on September 30, and lows from 54°F to 46°F. Normal precipitation for the month is 0.27 in over about 3 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
- 80°F
- Average low
- 50°F
- Precipitation
- 0.27 in
- Record high
- 103°FSep 2, 1987
- Record low
- 18°FSep 25, 1926
- Chance of a freeze
- 3%
- Days of 90°F or more
- 3.8
- Daylight
- 13 h 17 min to 11 h 44 min
- Cloud cover
- 40%
- Humidity
- 50%
- Dew point
- 43°F
- Wind
- 8.5 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 | 85°F | 54°F | 100°F 1967 | 37°F 1897 | 7% |
| Sep 2 | 85°F | 54°F | 103°F 1987 | 37°F 1919 | 7% |
| Sep 3 | 84°F | 53°F | 99°F 1998 | 37°F 1912 | 8% |
| Sep 4 | 84°F | 53°F | 99°F 1998 | 38°F 1912 | 8% |
| Sep 5 | 84°F | 53°F | 98°F 2003 | 36°F 1912 | 8% |
| Sep 6 | 83°F | 53°F | 98°F 1944 | 35°F 1895 | 8% |
| Sep 7 | 83°F | 52°F | 99°F 1944 | 34°F 1929 | 8% |
| Sep 8 | 83°F | 52°F | 97°F 1923 | 33°F 1908 | 8% |
| Sep 9 | 82°F | 52°F | 98°F 1935 | 31°F 1895 | 9% |
| Sep 10 | 82°F | 52°F | 96°F 1963 | 34°F 1913 | 9% |
| Sep 11 | 82°F | 51°F | 97°F 1944 | 34°F 2012 | 9% |
| Sep 12 | 81°F | 51°F | 99°F 1922 | 29°F 1921 | 9% |
| Sep 13 | 81°F | 51°F | 96°F 1923 | 27°F 1921 | 9% |
| Sep 14 | 81°F | 51°F | 95°F 1929 | 33°F 1915 | 9% |
| Sep 15 | 80°F | 50°F | 96°F 1938 | 31°F 1936 | 10% |
| Sep 16 | 80°F | 50°F | 96°F 1938 | 30°F 1936 | 10% |
| Sep 17 | 79°F | 50°F | 97°F 1938 | 30°F 1965 | 10% |
| Sep 18 | 79°F | 50°F | 95°F 1981 | 31°F 1909 | 10% |
| Sep 19 | 79°F | 49°F | 95°F 1952 | 35°F 1928 | 10% |
| Sep 20 | 78°F | 49°F | 95°F 1967 | 30°F 1895 | 10% |
| Sep 21 | 78°F | 49°F | 93°F 1936 | 30°F 1932 | 11% |
| Sep 22 | 77°F | 49°F | 97°F 1967 | 29°F 1955 | 11% |
| Sep 23 | 77°F | 48°F | 93°F 1966 | 30°F 1926 | 11% |
| Sep 24 | 76°F | 48°F | 92°F 1952 | 22°F 1926 | 11% |
| Sep 25 | 76°F | 48°F | 93°F 2001 | 18°F 1926 | 11% |
| Sep 26 | 76°F | 47°F | 97°F 1952 | 23°F 1926 | 11% |
| Sep 27 | 75°F | 47°F | 91°F 2003 | 26°F 1926 | 12% |
| Sep 28 | 75°F | 47°F | 94°F 1918 | 30°F 1916 | 12% |
| Sep 29 | 74°F | 47°F | 92°F 2003 | 26°F 1919 | 12% |
| Sep 30 | 74°F | 46°F | 90°F 1980 | 29°F 1919 | 12% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:20 AM, sunset 7:37 PM
- September 30
- sunrise 6:57 AM, sunset 6:41 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00456768 (Prosser), public domain. Records: NOAA GHCN-Daily, station USC00458207, 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.