August weather in St. Charles, MO
The average temperature in St. Charles in August is 76.3°F (65.8°F–86.8°F). Average precipitation: 4.07 inches.
August is a summer month in St. Charles, and is warmer than the annual average of 55.5°F. Daily temperatures swing about 21°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 13h 31m. For travel, August is a comfortable month to visit.
Avg High
86.8°F
Avg Low
65.8°F
Precipitation
4.07 in
Daylight
13h 31m
August records in St. Charles
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| August 1 | 102.9°F (1940) | 50.0°F (1971) | 2.20 in (1932) |
| August 2 | 108.0°F (1901) | 52.0°F (1971) | 1.75 in (1924) |
| August 3 | 106.0°F (1930) | 50.0°F (1971) | 2.51 in (1905) |
| August 4 | 109.0°F (1918) | 48.9°F (1912) | 2.25 in (2022) |
| August 5 | 107.1°F (1918) | 50.0°F (1925) | 1.87 in (2015) |
| August 6 | 105.1°F (1913) | 51.1°F (1994) | 4.12 in (2015) |
| August 7 | 107.1°F (1930) | 51.1°F (1994) | 2.42 in (1907) |
| August 8 | 111.0°F (1934) | 52.0°F (1976) | 4.45 in (1916) |
| August 9 | 111.9°F (1934) | 52.0°F (1976) | 3.29 in (2020) |
| August 10 | 109.0°F (1934) | 51.1°F (1972) | 1.04 in (1977) |
| August 11 | 106.0°F (1926) | 46.0°F (2000) | 1.47 in (1921) |
| August 12 | 108.0°F (1936) | 28.0°F (2000) | 2.55 in (1939) |
| August 13 | 108.0°F (1936) | 0.0°F (2000) | 1.66 in (1932) |
| August 14 | 105.1°F (1936) | 48.9°F (2004) | 1.87 in (2010) |
| August 15 | 109.9°F (1936) | 50.0°F (1992) | 3.06 in (1946) |
| August 16 | 108.0°F (1936) | 51.1°F (1979) | 5.42 in (1946) |
| August 17 | 108.0°F (1936) | 51.1°F (1992) | 2.02 in (2017) |
| August 18 | 109.9°F (1936) | 50.0°F (1943) | 2.80 in (1939) |
| August 19 | 111.0°F (1936) | 52.0°F (1981) | 1.30 in (1915) |
| August 20 | 107.1°F (1936) | 50.0°F (1950) | 5.90 in (1915) |
| August 21 | 106.0°F (1936) | 48.0°F (1950) | 2.05 in (1913) |
| August 22 | 107.1°F (1936) | 53.1°F (1949) | 1.77 in (2008) |
| August 23 | 106.0°F (1938) | 51.1°F (1966) | 1.55 in (1988) |
| August 24 | 106.0°F (1936) | 50.0°F (1920) | 2.10 in (1989) |
| August 25 | 102.9°F (1936) | 46.9°F (1958) | 2.96 in (1906) |
| August 26 | 108.0°F (1936) | 48.9°F (1910) | 1.78 in (1975) |
| August 27 | 105.1°F (1936) | 48.9°F (1910) | 1.48 in (2019) |
| August 28 | 102.9°F (1913) | 43.0°F (1986) | 1.56 in (1974) |
| August 29 | 100.9°F (1984) | 43.0°F (1986) | 2.11 in (1977) |
| August 30 | 107.1°F (1984) | 43.0°F (1986) | 1.38 in (1975) |
| August 31 | 102.0°F (1953) | 45.0°F (1915) | 1.96 in (1994) |