| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Tuesday, 10-Mar-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Mostly cloudy in the evening, becoming cloudy after midnight. Light to moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Thunderstorms very likely, some possibly severe. Breezy and unusually warm. Low 64°. Wind south-southwest around 12 mph, gusting to 30 mph. Chance of precipitation 80 percent. Precipitation mostly between a quarter and half an inch. |
| Wednesday |
Cloudy in the morning, becoming mostly cloudy in the afternoon. Light to moderate fog in the morning, then patchy light fog in the afternoon. Rain likely in the morning, then a slight chance of rain in the afternoon. Scattered thundershowers possible. Breezy and mild. High 65°, but temperatures falling in the afternoon. Wind west-northwest around 12 mph, gusting to 31 mph. Chance of precipitation 90 percent. Precipitation mostly around half an inch. |
| Wednesday night |
Fair to partly cloudy in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 36°. Wind northwest around 12 mph, gusting to 31 mph, in the evening, becoming 7 mph, gusting to 24 mph, after midnight. |
| Thursday |
Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. High 55°. UV index up to 4. Wind west-southwest around 5 mph, gusting to 23 mph, in the morning, becoming 8 mph, gusting to 24 mph, in the afternoon. |
| Thursday night |
Partly cloudy. Breezy. Low 40°. Wind south-southwest around 14 mph, gusting to 24 mph. |
| Friday |
Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Breezy. High 56°. UV index up to 4. Wind west around 11 mph, gusting to 28 mph, in the morning, becoming northwest in the afternoon. |
| Friday night |
Fair to partly cloudy in the evening, becoming mostly clear after midnight. Low 36°. Wind north-northeast around 5 mph, gusting to 20 mph, in the evening, becoming east-southeast after midnight. |
| Saturday |
Sunny in the morning, becoming partly to mostly cloudy in the afternoon. Mild. High 65°. Wind east-southeast around 10 mph, gusting to 23 mph, in the morning, becoming south in the afternoon. |
| Saturday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Low 50°. Wind south around 9 mph, gusting to 19 mph. |
| Sunday |
Mostly cloudy to cloudy in the morning, becoming dense overcast in the afternoon. A chance of rain in the morning, then rain likely in the afternoon. Precipitation showery or intermittent. Breezy and mild. High 65°, but temperatures falling in the afternoon. Wind south around 13 mph, gusting to 35 mph, in the morning, becoming west-northwest in the afternoon. Chance of precipitation 90 percent. Precipitation mostly around half an inch. |
| Sunday night |
Dense overcast in the evening, becoming cloudy after midnight. A chance of a mix of rain and snow in the evening, then a slight chance of snow after midnight. Windy and cold. Low 20°. Wind chill ranging from 10 to 37. Wind northwest around 18 mph, gusting to 36 mph. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Little or no snow accumulation expected. |
| Monday |
Mostly cloudy to cloudy. Breezy and very cold. High 22°. Wind chill around 8. Wind northwest around 15 mph, gusting to 31 mph. |
| Monday night |
Mostly clear. Very cold. Low 21°. Wind chill ranging from 9 to 16. Wind northwest around 9 mph, gusting to 23 mph, in the evening, becoming 5 mph, gusting to 18 mph, after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.