February in O'Fallon averages a daily high of 6°C with nights around -5°C. Expect roughly 8.5 wet days totalling 53.9mm. A hard month to visit for comfort alone.
Across the year, the best time to visit O'Fallon is September–October.
Based on ST PETERS 2 SE, MO US (10.7km), 1995–2024. 12 years of February data.