| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Tuesday, 26-May-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Partly to mostly cloudy. Patchy light fog after midnight. A chance of rain. Scattered thunderstorms likely. Low 66°. Wind east-northeast around 3 mph, gusting to 20 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Wednesday |
Mostly cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A chance of rain. Precipitation showery or intermittent. High 81°. UV index up to 7. Wind north-northeast around 4 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Wednesday night |
Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Light to moderate fog after midnight. A slight chance of rain. Low 62°. Wind northeast around 2 mph, gusting to 18 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Thursday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Light to moderate fog in the morning. High 83°. UV index up to 8. Wind northeast around 7 mph, gusting to 24 mph. |
| Thursday night |
Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Low 61°. Wind northeast around 6 mph, gusting to 21 mph. |
| Friday |
Cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. A slight chance of rain. Precipitation showery or intermittent. High 78°. UV index up to 5. Wind east around 7 mph, gusting to 24 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Friday night |
Partly to mostly cloudy. Low 62°. Wind east around 4 mph, gusting to 22 mph. |
| Saturday |
Partly cloudy. High 83°. UV index up to 7. Wind east-northeast around 6 mph, gusting to 25 mph. |
| Saturday night |
Partly cloudy. Low 59°. Wind east-northeast around 5 mph, gusting to 22 mph. |
| Sunday |
Partly cloudy. High 81°. UV index up to 7. Wind east-northeast around 7 mph, gusting to 25 mph. |
| Sunday night |
Partly cloudy. Relatively cool. Low 57°. Wind east-northeast around 4 mph, gusting to 23 mph. |
| Monday |
Mostly sunny in the morning, becoming sunny in the afternoon. High 79°. UV index up to 10. Wind east-northeast around 6 mph, gusting to 25 mph. |
| Monday night |
Clear. Relatively cool. Low 55°. Wind east-northeast around 4 mph, gusting to 22 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.