| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Tuesday, 09-Jun-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Partly to mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. A chance of rain. Scattered thundershowers possible. Very hot. High 96°. Heat index up to 106°. UV index up to 10. Wind southwest around 6 mph, gusting to 27 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Tonight |
Mostly clear. Patchy light fog after midnight. Low 75°. Wind southwest around 6 mph, gusting to 23 mph. |
| Wednesday |
Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Very hot. High 97°. Heat index up to 108°. UV index up to 9. Wind southwest around 9 mph, gusting to 29 mph. |
| Wednesday night |
Fair to partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Light to moderate fog after midnight. Low 75°. Wind south-southwest around 7 mph, gusting to 22 mph. |
| Thursday |
Mostly sunny. Light to moderate fog in the morning. A slight chance of rain in the afternoon. Scattered thundershowers possible. Very hot. High 94°. Heat index up to 105°. UV index up to 10. Wind south-southwest around 7 mph, gusting to 27 mph, in the morning, becoming 12 mph, gusting to 29 mph, in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Thursday night |
Mostly cloudy to cloudy in the evening, becoming partly to mostly cloudy after midnight. Light to moderate fog in the evening, then moderate fog after midnight. Rain likely. Scattered thunderstorms likely. Low 71°. Wind west around 8 mph, gusting to 23 mph. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch. |
| Friday |
Sunny in the morning, becoming partly to mostly sunny in the afternoon. Light to moderate fog in the morning. High 87°. UV index up to 8. Wind north-northwest around 5 mph, gusting to 24 mph. |
| Friday night |
Fair in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 66°. Wind north around 2 mph, gusting to 20 mph, in the evening, becoming south-southeast after midnight. |
| Saturday |
Partly cloudy. Patchy light fog in the morning. A chance of rain. Scattered thundershowers possible. High 84°. UV index up to 9. Wind south around 6 mph, gusting to 23 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch. |
| Saturday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Moderate fog. Rain likely. Scattered thundershowers possible. Low 72°. Wind south around 5 mph, gusting to 20 mph. Chance of precipitation 70 percent. Precipitation mostly between half an inch and one inch. |
| Sunday |
Dense overcast in the morning, becoming cloudy in the afternoon. Light to moderate fog. Rain likely in the morning, then a chance of rain in the afternoon. Scattered thunderstorms likely. High 75°. Wind west around 6 mph, gusting to 21 mph, in the morning, becoming north-northeast in the afternoon. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch. |
| Sunday night |
Mostly cloudy to cloudy. A slight chance of rain. Precipitation showery or intermittent. Low 66°. Wind north-northeast around 6 mph, gusting to 21 mph, in the evening, becoming northwest after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Monday |
Sunny in the morning, becoming partly cloudy in the afternoon. High 79°. UV index up to 10. Wind northwest around 10 mph, gusting to 29 mph. |
| Monday night |
Partly cloudy in the evening, becoming fair after midnight. Relatively cool. Low 59°. Wind northwest around 4 mph, gusting to 24 mph, in the evening, becoming west after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.