September weather in Grass Valley, CA
The average temperature in Grass Valley in September is 67.2°F (52.1°F–82.3°F). Average precipitation: 0.44 inches.
September is a fall month in Grass Valley, and is warmer than the annual average of 56.1°F. Daily temperatures swing about 30.2°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
82.3°F
Avg Low
52.1°F
Precipitation
0.44 in
Daylight
12h 14m
September records in Grass Valley
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 98.1°F (1998) | 45.0°F (1989) | 0.03 in (2003) |
| September 2 | 102.0°F (2017) | 46.0°F (1989) | 0.90 in (2000) |
| September 3 | 100.9°F (2017) | 45.0°F (1989) | 1.39 in (2013) |
| September 4 | 102.0°F (1988) | 43.0°F (2000) | 0.03 in (2023) |
| September 5 | 100.0°F (1988) | 42.1°F (1970) | 1.01 in (1978) |
| September 6 | 106.0°F (2022) | 45.0°F (1987) | 0.93 in (1978) |
| September 7 | 108.0°F (2022) | 43.0°F (1989) | 0.00 in (1967) |
| September 8 | 100.0°F (2020) | 42.1°F (1978) | 0.35 in (1985) |
| September 9 | 102.9°F (2022) | 41.0°F (1983) | 1.06 in (1985) |
| September 10 | 96.1°F (1984) | 36.0°F (1985) | 1.02 in (1978) |
| September 11 | 97.0°F (2015) | 37.9°F (1985) | 0.97 in (1976) |
| September 12 | 95.0°F (1983) | 37.9°F (1985) | 0.05 in (1976) |
| September 13 | 100.0°F (1971) | 42.1°F (1985) | 0.00 in (1967) |
| September 14 | 104.0°F (1971) | 41.0°F (1986) | 0.18 in (1996) |
| September 15 | 102.9°F (1971) | 39.0°F (1985) | 0.47 in (1997) |
| September 16 | 100.9°F (1971) | 39.9°F (2006) | 0.13 in (1982) |
| September 17 | 98.1°F (1971) | 41.0°F (1985) | 1.52 in (1989) |
| September 18 | 97.0°F (1984) | 36.0°F (1978) | 0.47 in (1967) |
| September 19 | 98.1°F (1984) | 36.0°F (1978) | 0.78 in (1989) |
| September 20 | 93.9°F (1974) | 36.0°F (1986) | 1.00 in (2022) |
| September 21 | 95.0°F (1974) | 37.9°F (1986) | 0.22 in (2013) |
| September 22 | 96.1°F (1994) | 37.9°F (1986) | 0.85 in (2013) |
| September 23 | 93.9°F (2003) | 39.0°F (1986) | 0.60 in (2000) |
| September 24 | 93.9°F (1974) | 37.9°F (1972) | 0.95 in (1982) |
| September 25 | 93.9°F (1974) | 37.9°F (1972) | 1.15 in (1981) |
| September 26 | 93.0°F (1975) | 39.9°F (1984) | 1.16 in (1982) |
| September 27 | 97.0°F (1967) | 37.9°F (1971) | 2.09 in (1986) |
| September 28 | 95.0°F (2009) | 35.1°F (1986) | 0.20 in (2021) |
| September 29 | 95.0°F (2010) | 35.1°F (2007) | 0.59 in (2007) |
| September 30 | 97.0°F (2010) | 36.0°F (1982) | 1.85 in (1983) |