Weather in O Fallon, IL
Updated 2026-09-26 09:00 local time · ZIP codes 62269
Overcast
No government weather alerts were returned for this location at the latest update.
Next hours
62°12% rain64°11% rain66°10% rain71°10% rain71°10% rain70°10% rain68°11% rain66°12% rain
64°15% rain62°20% rain
62°19% rain62°19% rain3-day weather forecast
Weather details
Sunrise, sunset and moon
Key weather changes ahead
Weather insights for today
Rain chance stays relatively low over the next 12 hours (up to 20%).
It feels like 57°F with winds near 6 mph.
70°F, 10% rain chance and 3 mph wind.
Visibility is around 6 mi; gusts may reach 14 mph.
Current temperature is 62°F, wind 6 mph, rain chance up to 20%.
UV index is 0.
Local weather characteristics in O Fallon
Illinois has four distinct seasons with hot, humid summers, cold winters, strong frontal changes and frequent spring and summer thunderstorms.
O Fallon is part of the Midwest weather region. The forecast point is near 38.59°N latitude and 89.91°W longitude. Local temperature, wind and precipitation can still differ from nearby places, especially where terrain, coastlines or urban development create small-scale weather changes.
O Fallon weather today
Overcast and 62°F in O Fallon, IL. Today's high is 71°F with a 18% rain chance. Winds are around 6 mph with gusts near 9 mph. Relative humidity is 52%, pressure is 30.15 inHg, and visibility is about 6 miles.
Tonight and tomorrow in O Fallon
Sunrise is at 06:51 AM and sunset is at 06:50 PM. Tomorrow's forecast calls for Sunny with a high near 75°F and a low near 56°F. The maximum rain chance is 57%.