Climate almanac
O'Fallon
Illinois, United States · 38.59°, -89.91°
What is the weather like in O'Fallon in October?
In October, O'Fallon is typically 71°F (22°C) during the day and 51°F (10°C) at night. The month brings about 3.4 in (86 mm) of precipitation in total.
- Average high71°F (22°C)
- Average low51°F (10°C)
- Precipitation3.4 in (86 mm)
- Clear or mostly clear days15
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)