Climate almanac
O'Fallon
Missouri, US · 38.81°, -90.70°
What is the climate like in O'Fallon?
O'Fallon is warmest in July, when daily highs average 88°F (31°C), and coolest in January, when lows fall to about 26°F (-3°C). The wettest month is typically May and the driest is December; the year sees roughly 43 in of precipitation.
- Warmest monthJuly — average high 88°F (31°C)
- Coolest monthJanuary — average low 26°F (-3°C)
- Wettest monthMay (5.2 in)
- Driest monthDecember (2.1 in)
- Annual precipitation43 in