January weather in O'Fallon, MO
The average temperature in O'Fallon in January is 30.3°F (21.2°F–39.3°F). Average precipitation: 2.61 inches. Average snowfall is 4.1 inches.
January is a winter month in O'Fallon, and is cooler than the annual average of 55.2°F. Daily temperatures swing about 18.1°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 9h 34m. For travel, January is cold.
Avg High
39.3°F
Avg Low
21.2°F
Precipitation
2.61 in
Snow
4.1 in
January records in O'Fallon
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| January 1 | 69.1°F (2005) | -9.9°F (1977) | 1.72 in (1985) |
| January 2 | 71.1°F (1997) | -0.9°F (2001) | 0.60 in (2003) |
| January 3 | 71.1°F (1997) | -6.0°F (1979) | 1.60 in (2005) |
| January 4 | 72.0°F (1997) | -5.1°F (1959) | 1.28 in (2004) |
| January 5 | 55.9°F (1982) | -11.0°F (1959) | 2.66 in (2005) |
| January 6 | 66.0°F (2012) | -9.0°F (2014) | 1.24 in (2025) |
| January 7 | 72.0°F (2008) | -11.0°F (1968) | 0.59 in (1998) |
| January 8 | 75.0°F (1965) | -8.0°F (2014) | 2.14 in (2008) |
| January 9 | 72.0°F (2006) | -6.0°F (1970) | 0.79 in (2024) |
| January 10 | 64.9°F (1963) | -11.9°F (1962) | 2.00 in (1975) |
| January 11 | 66.0°F (2017) | -18.0°F (1977) | 2.78 in (2020) |
| January 12 | 70.0°F (2017) | -11.9°F (1974) | 0.94 in (2019) |
| January 13 | 70.0°F (1995) | -9.9°F (1974) | 1.89 in (2005) |
| January 14 | 63.0°F (2026) | -8.0°F (2024) | 2.04 in (1995) |
| January 15 | 64.9°F (2016) | -17.0°F (1979) | 1.33 in (1969) |
| January 16 | 68.0°F (1990) | -15.0°F (1977) | 0.28 in (1978) |
| January 17 | 73.0°F (1990) | -23.1°F (1977) | 0.81 in (2012) |
| January 18 | 66.9°F (1986) | -11.9°F (1977) | 1.91 in (2020) |
| January 19 | 57.9°F (1973) | -14.1°F (1994) | 1.03 in (1995) |
| January 20 | 66.9°F (2006) | -6.0°F (1984) | 0.51 in (2011) |
| January 21 | 62.1°F (2006) | -18.9°F (1985) | 1.21 in (1959) |
| January 22 | 73.0°F (1986) | -9.0°F (1970) | 0.98 in (2018) |
| January 23 | 75.0°F (1967) | -11.0°F (1963) | 0.95 in (2024) |
| January 24 | 75.9°F (1967) | -9.9°F (1963) | 0.73 in (2010) |
| January 25 | 73.0°F (1967) | -8.0°F (1961) | 1.03 in (1967) |
| January 26 | 64.9°F (2018) | -4.0°F (1961) | 1.04 in (1989) |
| January 27 | 68.0°F (1999) | -6.0°F (1963) | 0.87 in (1997) |
| January 28 | 68.0°F (2002) | -14.1°F (1963) | 1.25 in (1969) |
| January 29 | 75.0°F (2002) | -9.0°F (1963) | 1.64 in (1969) |
| January 30 | 70.0°F (2008) | -8.0°F (1966) | 1.61 in (2013) |
| January 31 | 66.0°F (2012) | -11.9°F (1965) | 1.93 in (2002) |