September weather in Seattle, WA
The average temperature in Seattle in September is 62.8°F (53.9°F–71.7°F). Average precipitation: 1.37 inches.
September is a fall month in Seattle, and is warmer than the annual average of 53.8°F. Daily temperatures swing about 17.8°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 19m. For travel, September is one of the best months of the year to visit.
Avg High
71.7°F
Avg Low
53.9°F
Precipitation
1.37 in
Daylight
12h 19m
September records in Seattle
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 84.9°F (2006) | 46.0°F (2021) | 0.33 in (2004) |
| September 2 | 88.0°F (2017) | 43.0°F (1960) | 0.16 in (2002) |
| September 3 | 87.1°F (2003) | 44.1°F (1956) | 0.15 in (1950) |
| September 4 | 87.1°F (1963) | 45.0°F (1956) | 0.72 in (2007) |
| September 5 | 89.1°F (2024) | 45.0°F (1950) | 0.87 in (2013) |
| September 6 | 88.0°F (2014) | 46.0°F (1948) | 0.85 in (2009) |
| September 7 | 87.1°F (2014) | 45.0°F (1960) | 0.41 in (2019) |
| September 8 | 82.9°F (2011) | 45.0°F (1961) | 0.22 in (2010) |
| September 9 | 90.0°F (2020) | 46.0°F (1952) | 0.19 in (2018) |
| September 10 | 89.1°F (2020) | 43.0°F (1952) | 0.52 in (2004) |
| September 11 | 89.1°F (2013) | 41.0°F (1952) | 0.51 in (1956) |
| September 12 | 84.0°F (1961) | 41.0°F (1949) | 0.20 in (2004) |
| September 13 | 84.9°F (1957) | 42.1°F (1952) | 0.53 in (1955) |
| September 14 | 87.1°F (2000) | 48.0°F (1952) | 0.71 in (1949) |
| September 15 | 87.1°F (2014) | 43.0°F (1952) | 0.55 in (1959) |
| September 16 | 91.9°F (2025) | 42.1°F (1965) | 0.65 in (2003) |
| September 17 | 78.1°F (2012) | 42.1°F (1965) | 0.94 in (2010) |
| September 18 | 82.9°F (2009) | 41.0°F (1955) | 0.82 in (2010) |
| September 19 | 82.0°F (1999) | 39.9°F (1957) | 0.50 in (1959) |
| September 20 | 81.0°F (1963) | 41.0°F (1949) | 0.40 in (2008) |
| September 21 | 88.0°F (1952) | 41.0°F (1955) | 0.37 in (2025) |
| September 22 | 88.0°F (2009) | 32.0°F (2016) | 0.39 in (2013) |
| September 23 | 84.9°F (1957) | 41.0°F (1948) | 0.76 in (2020) |
| September 24 | 78.1°F (1957) | 37.9°F (1948) | 0.81 in (1950) |
| September 25 | 78.1°F (1963) | 37.9°F (1948) | 0.96 in (2023) |
| September 26 | 81.0°F (2022) | 43.0°F (1951) | 1.41 in (1948) |
| September 27 | 82.9°F (1963) | 43.0°F (1950) | 0.63 in (1953) |
| September 28 | 87.1°F (2017) | 39.9°F (1999) | 1.27 in (2013) |
| September 29 | 77.0°F (2020) | 37.9°F (1948) | 0.68 in (1951) |
| September 30 | 81.0°F (1957) | 36.0°F (1950) | 1.84 in (1953) |