September weather in Rio Dell, CA
The average temperature in Rio Dell in September is 62.2°F (51.9°F–72.5°F). Average precipitation: 0.47 inches.
September is a fall month in Rio Dell, and is warmer than the annual average of 55.6°F. Daily temperatures swing about 20.6°F between overnight low and afternoon high. Expect about 3 days with precipitation. Daylight averages about 12h 15m. For travel, September is one of the best months of the year to visit.
Avg High
72.5°F
Avg Low
51.9°F
Precipitation
0.47 in
Daylight
12h 15m
September records in Rio Dell
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 96.1°F (2017) | 44.1°F (1973) | 0.12 in (1944) |
| September 2 | 104.0°F (2017) | 45.0°F (1973) | 0.37 in (1941) |
| September 3 | 99.0°F (2017) | 45.0°F (1956) | 0.37 in (1940) |
| September 4 | 90.0°F (2017) | 44.1°F (1969) | 0.35 in (1940) |
| September 5 | 91.9°F (2020) | 44.1°F (1969) | 0.94 in (1978) |
| September 6 | 91.9°F (2020) | 45.0°F (1947) | 0.17 in (1978) |
| September 7 | 95.0°F (1958) | 42.1°F (1960) | 0.31 in (1947) |
| September 8 | 89.1°F (1958) | 41.0°F (1996) | 0.50 in (2025) |
| September 9 | 88.0°F (1944) | 43.0°F (1952) | 0.97 in (2025) |
| September 10 | 95.0°F (1973) | 44.1°F (1988) | 0.79 in (1978) |
| September 11 | 88.0°F (1929) | 41.0°F (1988) | 0.17 in (1958) |
| September 12 | 86.0°F (2000) | 39.9°F (1970) | 0.25 in (1928) |
| September 13 | 95.0°F (1979) | 37.9°F (1970) | 0.33 in (2009) |
| September 14 | 91.0°F (1979) | 37.9°F (1970) | 0.61 in (1955) |
| September 15 | 86.0°F (1952) | 42.1°F (1944) | 0.68 in (1935) |
| September 16 | 95.0°F (1971) | 42.1°F (1969) | 1.04 in (1986) |
| September 17 | 89.1°F (1951) | 39.9°F (1965) | 0.63 in (1986) |
| September 18 | 90.0°F (2000) | 39.9°F (1965) | 1.34 in (1959) |
| September 19 | 89.1°F (2002) | 39.9°F (1988) | 1.42 in (1977) |
| September 20 | 91.9°F (1939) | 42.1°F (1932) | 0.97 in (1973) |
| September 21 | 97.0°F (1939) | 39.9°F (1970) | 0.78 in (2013) |
| September 22 | 95.0°F (2003) | 39.9°F (1960) | 0.78 in (2013) |
| September 23 | 93.9°F (2003) | 42.1°F (1945) | 0.88 in (1973) |
| September 24 | 95.0°F (1964) | 39.9°F (1970) | 1.28 in (2014) |
| September 25 | 98.1°F (1964) | 39.9°F (1984) | 1.18 in (2023) |
| September 26 | 90.0°F (2016) | 39.9°F (1984) | 0.69 in (1957) |
| September 27 | 89.1°F (1970) | 41.0°F (1945) | 2.01 in (1957) |
| September 28 | 86.0°F (1970) | 42.1°F (1945) | 0.28 in (1977) |
| September 29 | 91.0°F (1966) | 39.9°F (1959) | 0.92 in (1962) |
| September 30 | 95.0°F (1966) | 37.0°F (1950) | 1.08 in (1971) |