September weather in Sebastopol, CA
The average temperature in Sebastopol in September is 65.9°F (48.0°F–83.7°F). Average precipitation: 0.18 inches.
September is a fall month in Sebastopol, and is warmer than the annual average of 57.9°F. Daily temperatures swing about 35.7°F between overnight low and afternoon high. Expect about 2 days with precipitation. Daylight averages about 12h 14m. For travel, September is a comfortable month to visit.
Avg High
83.7°F
Avg Low
48.0°F
Precipitation
0.18 in
Daylight
12h 14m
September records in Sebastopol
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 111.9°F (2017) | 39.9°F (1957) | 0.53 in (1983) |
| September 2 | 109.9°F (2017) | 37.9°F (1970) | 0.65 in (2000) |
| September 3 | 106.0°F (1950) | 39.0°F (1970) | 0.09 in (2003) |
| September 4 | 102.9°F (2022) | 39.0°F (2016) | 0.02 in (1949) |
| September 5 | 111.9°F (2022) | 39.0°F (1950) | 0.03 in (1935) |
| September 6 | 115.0°F (2022) | 39.0°F (1973) | 0.21 in (1978) |
| September 7 | 113.0°F (2020) | 39.0°F (1951) | 0.13 in (1985) |
| September 8 | 107.1°F (2022) | 37.9°F (1928) | 0.81 in (1985) |
| September 9 | 109.0°F (1932) | 37.0°F (2012) | 0.09 in (2025) |
| September 10 | 104.0°F (2015) | 34.0°F (1928) | 1.34 in (1978) |
| September 11 | 102.9°F (2015) | 39.0°F (1928) | 0.04 in (1954) |
| September 12 | 105.1°F (1979) | 39.0°F (1934) | 0.17 in (1940) |
| September 13 | 109.0°F (1979) | 37.9°F (1970) | 0.22 in (2017) |
| September 14 | 109.9°F (1971) | 34.0°F (1970) | 0.35 in (1955) |
| September 15 | 111.9°F (1971) | 33.1°F (1970) | 0.39 in (1997) |
| September 16 | 106.0°F (1971) | 34.0°F (1970) | 0.69 in (1986) |
| September 17 | 100.0°F (1935) | 37.0°F (1970) | 0.97 in (1989) |
| September 18 | 102.0°F (1984) | 35.1°F (2008) | 4.18 in (1959) |
| September 19 | 102.0°F (1984) | 35.1°F (1926) | 1.01 in (1977) |
| September 20 | 106.0°F (1939) | 28.0°F (2012) | 0.42 in (1973) |
| September 21 | 108.0°F (1939) | 36.0°F (2012) | 0.42 in (2013) |
| September 22 | 108.0°F (1939) | 36.0°F (2017) | 0.18 in (1999) |
| September 23 | 108.0°F (1939) | 33.1°F (1972) | 0.40 in (1973) |
| September 24 | 106.0°F (1936) | 36.0°F (1931) | 0.35 in (1986) |
| September 25 | 104.0°F (2019) | 35.1°F (1948) | 0.25 in (1981) |
| September 26 | 100.0°F (2010) | 36.0°F (1929) | 0.60 in (1957) |
| September 27 | 107.1°F (2020) | 35.1°F (1926) | 2.30 in (1957) |
| September 28 | 105.1°F (2010) | 36.0°F (1971) | 0.28 in (1976) |
| September 29 | 105.1°F (2010) | 34.0°F (2007) | 0.66 in (1977) |
| September 30 | 100.9°F (1990) | 34.0°F (1950) | 0.33 in (1971) |