| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Friday, 20-Mar-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 46°. Wind north-northwest around 3 mph, gusting to 26 mph, in the evening, becoming east-northeast after midnight. |
| Saturday |
Sunny. Patchy light fog in the morning. Unusually warm. High 81°. UV index up to 6. Wind east-southeast around 3 mph, gusting to 20 mph, in the morning, becoming south in the afternoon. |
| Saturday night |
Clear in the evening, becoming mostly clear after midnight. Low 50°. Wind south around 4 mph in the evening, becoming 8 mph after midnight. |
| Sunday |
Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Unusually hot. High 83°. UV index up to 5. Wind south-southwest around 9 mph, gusting to 29 mph, in the morning, becoming north-northwest in the afternoon. |
| Sunday night |
Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Low 39°. Wind north-northwest around 12 mph, gusting to 29 mph, in the evening, becoming 9 mph, gusting to 25 mph, after midnight. |
| Monday |
Partly cloudy. High 59°. UV index up to 5. Wind north-northeast around 7 mph, gusting to 26 mph. |
| Monday night |
Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. A slight chance of rain after midnight. Low 39°. Wind east-northeast around 5 mph, gusting to 22 mph, in the evening, becoming east-southeast after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Tuesday |
Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Mild. High 68°. UV index up to 6. Wind southeast around 5 mph, gusting to 25 mph. |
| Tuesday night |
Partly cloudy. Low 42°. Wind southeast around 3 mph, gusting to 19 mph. |
| Wednesday |
Mostly cloudy to cloudy. A slight chance of rain. Mild. High 67°. Wind southeast around 4 mph, gusting to 16 mph, in the morning, becoming 8 mph, gusting to 21 mph, in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Wednesday night |
Fair in the evening, becoming mostly clear after midnight. Low 44°. Wind south-southeast around 7 mph, gusting to 18 mph. |
| Thursday |
Mostly sunny in the morning, becoming mostly cloudy in the afternoon. Breezy and unusually warm. High 77°. UV index up to 5. Wind southwest around 9 mph, gusting to 29 mph, in the morning, becoming north-northwest around 15 mph, gusting to 30 mph, in the afternoon. |
| Thursday night |
Mostly clear in the evening, becoming clear after midnight. Breezy. Low 36°. Wind north around 11 mph, gusting to 28 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.