September weather in St. Charles, MO
The average temperature in St. Charles in September is 68.8°F (57.2°F–80.4°F). Average precipitation: 3.08 inches.
September is a fall month in St. Charles, and is warmer than the annual average of 55.5°F. Daily temperatures swing about 23.2°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 12h 14m. For travel, September is a comfortable month to visit.
Avg High
80.4°F
Avg Low
57.2°F
Precipitation
3.08 in
Daylight
12h 14m
September records in St. Charles
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 104.0°F (1953) | 46.0°F (1967) | 1.95 in (2021) |
| September 2 | 102.9°F (1954) | 48.0°F (1967) | 3.23 in (2014) |
| September 3 | 105.1°F (1913) | 43.0°F (1974) | 1.81 in (1993) |
| September 4 | 106.0°F (1954) | 39.0°F (1974) | 4.09 in (1910) |
| September 5 | 106.0°F (1954) | 39.0°F (1974) | 2.27 in (2008) |
| September 6 | 105.1°F (1925) | 41.0°F (1974) | 1.93 in (1971) |
| September 7 | 102.0°F (1899) | 44.1°F (1988) | 1.23 in (1911) |
| September 8 | 102.9°F (1938) | 39.0°F (1986) | 3.30 in (1920) |
| September 9 | 104.0°F (1925) | 41.0°F (1986) | 2.88 in (1984) |
| September 10 | 100.9°F (1933) | 45.0°F (1969) | 1.34 in (2016) |
| September 11 | 100.9°F (1938) | 39.0°F (1917) | 2.30 in (1984) |
| September 12 | 102.0°F (1936) | 43.0°F (1955) | 3.71 in (1913) |
| September 13 | 102.0°F (1936) | 36.0°F (1902) | 1.91 in (1945) |
| September 14 | 102.0°F (1893) | 41.0°F (1902) | 3.52 in (2008) |
| September 15 | 104.0°F (1939) | 39.0°F (1979) | 1.88 in (1993) |
| September 16 | 100.0°F (1927) | 39.0°F (1979) | 3.83 in (1911) |
| September 17 | 99.0°F (1954) | 32.0°F (2006) | 2.38 in (1969) |
| September 18 | 102.0°F (1925) | 33.1°F (1901) | 2.15 in (1968) |
| September 19 | 98.1°F (1925) | 33.1°F (1901) | 1.41 in (1900) |
| September 20 | 100.0°F (1948) | 34.0°F (1901) | 2.80 in (1954) |
| September 21 | 99.0°F (1955) | 37.0°F (1918) | 2.89 in (1919) |
| September 22 | 98.1°F (1937) | 36.0°F (1991) | 2.22 in (1908) |
| September 23 | 95.0°F (1939) | 34.0°F (1995) | 2.33 in (1955) |
| September 24 | 97.0°F (1938) | 30.9°F (1983) | 1.75 in (1996) |
| September 25 | 93.9°F (1939) | 33.1°F (1989) | 2.07 in (1941) |
| September 26 | 95.0°F (1953) | 36.0°F (1989) | 2.28 in (2012) |
| September 27 | 91.0°F (2017) | 35.1°F (1985) | 2.45 in (1933) |
| September 28 | 100.0°F (1953) | 30.9°F (1942) | 2.50 in (1919) |
| September 29 | 105.1°F (1953) | 34.0°F (1908) | 2.58 in (1927) |
| September 30 | 96.1°F (1952) | 30.9°F (1899) | 1.94 in (1926) |