September weather in Sumner, WA
The average temperature in Sumner in September is 58.9°F (48.2°F–69.6°F). Average precipitation: 1.78 inches.
September is a fall month in Sumner, and is warmer than the annual average of 50.5°F. Daily temperatures swing about 21.4°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 12h 19m. For travel, September is a comfortable month to visit.
Avg High
69.6°F
Avg Low
48.2°F
Precipitation
1.78 in
Daylight
12h 19m
September records in Sumner
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 90.0°F (1987) | 37.9°F (1973) | 0.61 in (1983) |
| September 2 | 90.0°F (1987) | 37.0°F (1984) | 1.64 in (1971) |
| September 3 | 95.0°F (1988) | 37.9°F (1958) | 1.19 in (1979) |
| September 4 | 91.0°F (1988) | 39.0°F (1952) | 1.39 in (1945) |
| September 5 | 88.0°F (1962) | 35.1°F (1947) | 0.94 in (1945) |
| September 6 | 93.0°F (1944) | 39.0°F (1960) | 2.72 in (2013) |
| September 7 | 89.1°F (1949) | 37.0°F (1960) | 0.94 in (2009) |
| September 8 | 93.0°F (1981) | 39.0°F (1961) | 1.18 in (2010) |
| September 9 | 86.0°F (1943) | 36.0°F (1959) | 1.24 in (1994) |
| September 10 | 86.0°F (1944) | 36.0°F (1952) | 0.55 in (1941) |
| September 11 | 90.0°F (1944) | 37.9°F (1988) | 0.99 in (2004) |
| September 12 | 87.1°F (2022) | 34.0°F (1970) | 0.47 in (1966) |
| September 13 | 84.9°F (1961) | 30.0°F (1970) | 0.43 in (2004) |
| September 14 | 84.9°F (1957) | 35.1°F (1970) | 0.74 in (1955) |
| September 15 | 91.9°F (1979) | 34.0°F (1969) | 0.79 in (1996) |
| September 16 | 89.1°F (1951) | 37.0°F (1965) | 1.06 in (1946) |
| September 17 | 89.1°F (2025) | 34.0°F (1965) | 0.67 in (1954) |
| September 18 | 82.9°F (1981) | 34.0°F (1944) | 1.46 in (1969) |
| September 19 | 84.0°F (1991) | 34.0°F (1983) | 0.59 in (1988) |
| September 20 | 82.0°F (1999) | 33.1°F (1983) | 0.84 in (1959) |
| September 21 | 84.9°F (1952) | 34.0°F (1960) | 1.15 in (1972) |
| September 22 | 91.0°F (1952) | 34.0°F (1961) | 0.64 in (1948) |
| September 23 | 89.1°F (1990) | 34.0°F (1996) | 1.81 in (1978) |
| September 24 | 84.0°F (1947) | 32.0°F (1984) | 1.14 in (2014) |
| September 25 | 89.1°F (1943) | 30.9°F (1972) | 0.78 in (1950) |
| September 26 | 82.9°F (1991) | 34.0°F (1972) | 0.87 in (1950) |
| September 27 | 81.0°F (2022) | 28.9°F (1972) | 0.96 in (1948) |
| September 28 | 90.0°F (1967) | 30.0°F (1983) | 0.74 in (1948) |
| September 29 | 82.9°F (2017) | 30.9°F (1983) | 0.60 in (2007) |
| September 30 | 81.0°F (1992) | 32.0°F (1954) | 1.38 in (1951) |