| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Tuesday, 21-Apr-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Partly cloudy in the morning, becoming sunny in the afternoon. Warm. High 78°. UV index up to 7. Wind west-southwest around 9 mph, gusting to 29 mph, in the morning, becoming 12 mph, gusting to 30 mph, in the afternoon. |
| Tonight |
Clear in the evening, becoming mostly clear after midnight. Low 52°. Wind west-southwest around 8 mph, gusting to 25 mph. |
| Wednesday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Warm. High 77°. UV index up to 7. Wind west-southwest around 7 mph, gusting to 26 mph. |
| Wednesday night |
Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 53°. Wind south around 4 mph, gusting to 19 mph. |
| Thursday |
Partly cloudy. Patchy light fog in the morning. A slight chance of rain in the afternoon. Scattered thundershowers possible. Warm. High 79°. UV index up to 7. Wind south-southeast around 8 mph, gusting to 25 mph, in the morning, becoming 12 mph, gusting to 29 mph, in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Thursday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog after midnight. Rain likely. Scattered thundershowers possible. Low 60°. Wind south-southeast around 10 mph, gusting to 22 mph. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch. |
| Friday |
Cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. Rain likely. Scattered thunderstorms likely. Warm. High 76°. UV index up to 5. Wind south around 9 mph, gusting to 25 mph, in the morning, becoming southwest in the afternoon. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch. |
| Friday night |
Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Light to moderate fog in the evening, then moderate fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 56°. Wind northwest around 6 mph, gusting to 20 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch. |
| Saturday |
Sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. Warm. High 75°. UV index up to 6. Wind north-northeast around 6 mph, gusting to 24 mph. |
| Saturday night |
Partly cloudy. Patchy light fog after midnight. Low 52°. Wind northeast around 6 mph, gusting to 18 mph. |
| Sunday |
Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 73°. UV index up to 6. Wind east around 9 mph, gusting to 26 mph. |
| Sunday night |
Mostly cloudy in the evening, becoming cloudy after midnight. Patchy light fog after midnight. A slight chance of rain in the evening, then rain likely after midnight. Precipitation showery or intermittent. Breezy. Low 54°. Wind east-southeast around 11 mph, gusting to 24 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch. |
| Monday |
Cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. Patchy light fog. Rain very likely. Scattered thunderstorms likely. Breezy. High 67°. UV index up to 5. Wind south-southeast around 13 mph, gusting to 23 mph, in the morning, becoming southwest in the afternoon. Chance of precipitation 80 percent. Precipitation mostly around an inch. |
| Monday night |
Mostly cloudy to cloudy in the evening, becoming partly cloudy after midnight. Breezy. Low 53°. Wind west-northwest around 11 mph, gusting to 27 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.