September weather in Mill Valley, CA
The average temperature in Mill Valley in September is °F (°F–°F). Average precipitation: 0.19 inches.
September is a fall month in Mill Valley, and is cooler than the annual average of 0°F. Expect about 3 days with precipitation. Daylight averages about 12h 14m.
Avg High
°F
Avg Low
°F
Precipitation
0.19 in
Daylight
12h 14m
September records in Mill Valley
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 84.0°F (2013) | 45.0°F (2016) | 0.02 in (2001) |
| September 2 | 82.0°F (2014) | 48.0°F (2016) | 0.22 in (1941) |
| September 3 | 90.0°F (2013) | 46.0°F (2016) | 0.01 in (1998) |
| September 4 | 84.9°F (2013) | 50.0°F (2016) | 0.02 in (1978) |
| September 5 | 86.0°F (2013) | 45.0°F (2015) | 0.05 in (1978) |
| September 6 | 91.0°F (2013) | 46.0°F (2016) | 0.05 in (1985) |
| September 7 | 93.0°F (2013) | 46.0°F (2014) | 0.01 in (1999) |
| September 8 | 102.9°F (2015) | 44.1°F (2016) | 0.46 in (1985) |
| September 9 | 100.0°F (2015) | 46.0°F (2014) | 0.36 in (1978) |
| September 10 | 86.0°F (2014) | 53.1°F (2013) | 0.28 in (1952) |
| September 11 | 79.0°F (2014) | 55.0°F (2014) | 0.07 in (2013) |
| September 12 | 81.0°F (2015) | 37.0°F (2016) | 0.05 in (1963) |
| September 13 | 84.0°F (2015) | 43.0°F (2016) | 0.05 in (1963) |
| September 14 | 79.0°F (2014) | 48.0°F (2016) | 0.50 in (2009) |
| September 15 | 81.0°F (2014) | 48.9°F (2013) | 0.65 in (1996) |
| September 16 | 81.0°F (2014) | 50.0°F (2014) | 0.52 in (1989) |
| September 17 | 84.0°F (2013) | 50.0°F (2013) | 0.43 in (1989) |
| September 18 | 84.0°F (2013) | 50.0°F (2013) | 1.86 in (1959) |
| September 19 | 97.0°F (2016) | 45.0°F (2013) | 0.81 in (1977) |
| September 20 | 93.0°F (2015) | 45.0°F (2013) | 2.06 in (1973) |
| September 21 | 84.9°F (2013) | 45.0°F (2013) | 0.43 in (2013) |
| September 22 | 87.1°F (2015) | 46.9°F (2016) | 0.42 in (1973) |
| September 23 | 84.0°F (2016) | 46.0°F (2014) | 0.14 in (1983) |
| September 24 | 84.0°F (2013) | 51.1°F (2013) | 1.36 in (1986) |
| September 25 | 91.9°F (2015) | 51.1°F (2013) | 0.41 in (2014) |
| September 26 | 84.0°F (2015) | 42.1°F (2014) | 0.76 in (1972) |
| September 27 | 97.0°F (2016) | 37.0°F (2014) | 0.62 in (1972) |
| September 28 | 82.0°F (2013) | 48.9°F (2013) | 0.86 in (1957) |
| September 29 | 81.0°F (2013) | 44.1°F (2013) | 1.53 in (1962) |
| September 30 | 75.0°F (2014) | 48.0°F (2014) | 0.24 in (1951) |