September weather in Clearlake, CA
The average temperature in Clearlake in September is 67.9°F (50.3°F–85.4°F). Average precipitation: 0.17 inches.
September is a fall month in Clearlake, and is warmer than the annual average of 56.9°F. Daily temperatures swing about 35.1°F between overnight low and afternoon high. Expect about 1 days with precipitation. Daylight averages about 12h 14m. For travel, September is a comfortable month to visit.
Avg High
85.4°F
Avg Low
50.3°F
Precipitation
0.17 in
Daylight
12h 14m
September records in Clearlake
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 105.1°F (1955) | 39.9°F (1957) | 0.13 in (1983) |
| September 2 | 109.9°F (1955) | 37.0°F (1964) | 0.21 in (2000) |
| September 3 | 111.0°F (1955) | 37.9°F (1964) | 0.04 in (2000) |
| September 4 | 111.0°F (1955) | 39.9°F (1965) | 0.05 in (2003) |
| September 5 | 105.1°F (1988) | 36.0°F (1996) | 0.00 in (1955) |
| September 6 | 109.0°F (2022) | 36.0°F (1996) | 2.00 in (1998) |
| September 7 | 113.0°F (2022) | 37.9°F (1996) | 0.02 in (1985) |
| September 8 | 106.0°F (1957) | 35.1°F (1966) | 0.52 in (1985) |
| September 9 | 107.1°F (2022) | 35.1°F (1964) | 0.36 in (1985) |
| September 10 | 106.0°F (2022) | 35.1°F (1964) | 0.10 in (1985) |
| September 11 | 109.0°F (2020) | 34.0°F (1964) | 0.07 in (1976) |
| September 12 | 100.9°F (1981) | 37.0°F (1965) | 0.00 in (1955) |
| September 13 | 102.0°F (1971) | 37.0°F (1964) | 0.09 in (1966) |
| September 14 | 106.0°F (1979) | 33.1°F (1966) | 0.20 in (1955) |
| September 15 | 104.0°F (1971) | 34.0°F (1970) | 0.37 in (1997) |
| September 16 | 102.0°F (1971) | 37.9°F (1964) | 0.33 in (1982) |
| September 17 | 100.9°F (1971) | 39.9°F (1964) | 2.81 in (1989) |
| September 18 | 98.1°F (1962) | 41.0°F (1964) | 1.49 in (1959) |
| September 19 | 102.0°F (1974) | 30.0°F (1965) | 0.58 in (1977) |
| September 20 | 100.9°F (2000) | 30.9°F (1965) | 0.21 in (1973) |
| September 21 | 102.0°F (1987) | 36.0°F (1965) | 0.07 in (2013) |
| September 22 | 100.0°F (1987) | 36.0°F (1956) | 0.08 in (1986) |
| September 23 | 98.1°F (1974) | 37.9°F (1956) | 0.43 in (1990) |
| September 24 | 102.0°F (1967) | 37.0°F (1970) | 0.27 in (2001) |
| September 25 | 102.0°F (1964) | 36.0°F (2007) | 0.56 in (1981) |
| September 26 | 100.0°F (2009) | 34.0°F (1955) | 0.78 in (1972) |
| September 27 | 102.0°F (1963) | 33.1°F (1955) | 1.28 in (1957) |
| September 28 | 100.0°F (1963) | 35.1°F (1964) | 0.31 in (1957) |
| September 29 | 99.0°F (2018) | 35.1°F (1955) | 0.62 in (1989) |
| September 30 | 102.0°F (1966) | 33.1°F (1955) | 0.09 in (1971) |