September weather in Prosser, WA
The average temperature in Prosser in September is 64.9°F (50.1°F–79.7°F). Average precipitation: 0.27 inches.
September is a fall month in Prosser, and is warmer than the annual average of 53°F. Daily temperatures swing about 29.6°F between overnight low and afternoon high. Expect about 3 days with precipitation. Daylight averages about 12h 19m. For travel, September is one of the best months of the year to visit.
Avg High
79.7°F
Avg Low
50.1°F
Precipitation
0.27 in
Daylight
12h 19m
September records in Prosser
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 108.0°F (1986) | 39.9°F (1971) | 0.52 in (1939) |
| September 2 | 97.0°F (1949) | 37.0°F (1932) | 0.51 in (1971) |
| September 3 | 100.0°F (2025) | 32.0°F (1930) | 0.35 in (1941) |
| September 4 | 100.0°F (2025) | 37.9°F (1969) | 0.12 in (1960) |
| September 5 | 99.0°F (2003) | 39.0°F (1956) | 0.32 in (1937) |
| September 6 | 97.0°F (1955) | 39.0°F (1961) | 0.39 in (2013) |
| September 7 | 99.0°F (1944) | 37.0°F (1929) | 0.41 in (1947) |
| September 8 | 96.1°F (1944) | 35.1°F (2001) | 0.14 in (2003) |
| September 9 | 96.1°F (1996) | 33.1°F (2010) | 0.25 in (1933) |
| September 10 | 95.0°F (1943) | 37.0°F (1972) | 0.74 in (1985) |
| September 11 | 97.0°F (1944) | 37.9°F (1936) | 0.37 in (2021) |
| September 12 | 95.0°F (2011) | 37.0°F (1949) | 0.02 in (1978) |
| September 13 | 98.1°F (2011) | 33.1°F (1936) | 0.44 in (1980) |
| September 14 | 95.0°F (2011) | 33.1°F (1936) | 0.38 in (1980) |
| September 15 | 95.0°F (1996) | 30.0°F (1936) | 0.39 in (1949) |
| September 16 | 95.0°F (1938) | 32.0°F (1936) | 0.31 in (1986) |
| September 17 | 91.0°F (1938) | 30.9°F (1965) | 0.31 in (1954) |
| September 18 | 91.9°F (1981) | 30.9°F (1965) | 0.40 in (1969) |
| September 19 | 93.0°F (1952) | 34.0°F (1971) | 0.64 in (2010) |
| September 20 | 91.0°F (1967) | 32.0°F (1983) | 0.55 in (1982) |
| September 21 | 91.9°F (1936) | 30.9°F (1971) | 0.13 in (2008) |
| September 22 | 95.0°F (1967) | 30.0°F (1996) | 0.28 in (1934) |
| September 23 | 90.0°F (1966) | 21.9°F (2000) | 0.23 in (1933) |
| September 24 | 91.9°F (1999) | 21.0°F (2000) | 0.98 in (1986) |
| September 25 | 93.0°F (2001) | 21.0°F (1926) | 0.20 in (1982) |
| September 26 | 91.0°F (1952) | 28.9°F (1926) | 0.32 in (1982) |
| September 27 | 90.0°F (1952) | 28.9°F (1972) | 0.66 in (1981) |
| September 28 | 88.0°F (2003) | 32.0°F (1945) | 0.39 in (1957) |
| September 29 | 90.0°F (1996) | 28.9°F (1971) | 0.33 in (1927) |
| September 30 | 89.1°F (1976) | 30.9°F (1933) | 0.44 in (1951) |