September weather in Walla Walla, WA
The average temperature in Walla Walla in September is 66.2°F (53.9°F–78.5°F). Average precipitation: 0.64 inches.
September is a fall month in Walla Walla, and is warmer than the annual average of 54.3°F. Daily temperatures swing about 24.6°F between overnight low and afternoon high. Expect about 4 days with precipitation. Daylight averages about 12h 18m. For travel, September is one of the best months of the year to visit.
Avg High
78.5°F
Avg Low
53.9°F
Precipitation
0.64 in
Daylight
12h 18m
September records in Walla Walla
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 99.0°F (1987) | 44.1°F (1999) | 0.94 in (1971) |
| September 2 | 104.0°F (1950) | 44.1°F (1999) | 0.51 in (1971) |
| September 3 | 96.1°F (1993) | 44.1°F (1958) | 1.04 in (1970) |
| September 4 | 99.0°F (2020) | 44.1°F (1956) | 0.71 in (1960) |
| September 5 | 99.0°F (1955) | 44.1°F (1956) | 0.72 in (2015) |
| September 6 | 102.0°F (1955) | 45.0°F (1960) | 0.25 in (1978) |
| September 7 | 98.1°F (1958) | 44.1°F (1960) | 0.58 in (1970) |
| September 8 | 102.0°F (1981) | 39.0°F (1962) | 1.69 in (2003) |
| September 9 | 97.0°F (1963) | 43.0°F (1962) | 0.61 in (1982) |
| September 10 | 99.0°F (1990) | 43.0°F (1964) | 1.34 in (1962) |
| September 11 | 97.0°F (1953) | 43.0°F (1999) | 0.49 in (1967) |
| September 12 | 95.0°F (2011) | 41.0°F (1964) | 0.33 in (1980) |
| September 13 | 93.9°F (2013) | 37.9°F (1970) | 0.89 in (1980) |
| September 14 | 97.0°F (2013) | 39.0°F (1970) | 0.86 in (1955) |
| September 15 | 98.1°F (1979) | 39.0°F (1970) | 0.84 in (1949) |
| September 16 | 97.0°F (1981) | 35.1°F (1965) | 0.33 in (1985) |
| September 17 | 97.0°F (1981) | 32.0°F (1965) | 0.52 in (2013) |
| September 18 | 97.0°F (1981) | 36.0°F (1965) | 0.58 in (1968) |
| September 19 | 91.9°F (1994) | 33.1°F (1957) | 0.48 in (2010) |
| September 20 | 91.9°F (1967) | 37.0°F (1983) | 0.52 in (1973) |
| September 21 | 93.9°F (1967) | 39.0°F (1971) | 0.66 in (1972) |
| September 22 | 90.0°F (1999) | 37.0°F (1993) | 0.41 in (2014) |
| September 23 | 93.0°F (2011) | 33.1°F (2000) | 0.62 in (1984) |
| September 24 | 95.0°F (1952) | 37.0°F (2000) | 0.36 in (1992) |
| September 25 | 99.0°F (1952) | 37.0°F (1970) | 0.62 in (1982) |
| September 26 | 91.9°F (1952) | 37.9°F (1972) | 0.70 in (1959) |
| September 27 | 90.0°F (1967) | 35.1°F (1972) | 0.55 in (1957) |
| September 28 | 90.0°F (1967) | 34.0°F (1985) | 0.54 in (1962) |
| September 29 | 90.0°F (1976) | 32.0°F (1985) | 0.43 in (1986) |
| September 30 | 89.1°F (1976) | 34.0°F (2019) | 0.60 in (1951) |