| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Monday, 27-Apr-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. A chance of rain in the evening. Scattered thunderstorms likely. Low 58°. Wind west-southwest around 7 mph, gusting to 21 mph. Chance of precipitation 60 percent. Precipitation mostly less than a tenth of an inch. |
| Tuesday |
Mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Precipitation showery or intermittent. High 74°. UV index up to 6. Wind northwest around 5 mph, gusting to 27 mph. Chance of precipitation 50 percent. Precipitation mostly less than a tenth of an inch. |
| Tuesday night |
Mostly cloudy to cloudy in the evening, becoming partly cloudy after midnight. Light to moderate fog. Rain likely in the evening, then a slight chance of rain after midnight. Precipitation showery or intermittent. Low 53°. Wind north-northeast around 5 mph, gusting to 19 mph. Chance of precipitation 70 percent. Precipitation mostly around a quarter of an inch. |
| Wednesday |
Sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. High 66°. UV index up to 6. Wind north-northwest around 10 mph, gusting to 28 mph. |
| Wednesday night |
Fair in the evening, becoming clear after midnight. Cool. Low 44°. Wind north-northwest around 7 mph, gusting to 24 mph, in the evening, becoming 2 mph after midnight. |
| Thursday |
Partly to mostly sunny in the morning, becoming mostly cloudy in the afternoon. A chance of rain in the afternoon. Scattered thundershowers possible. High 67°. UV index up to 6. Wind south-southwest around 4 mph, gusting to 27 mph, in the morning, becoming west-southwest in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Thursday night |
Cloudy in the evening, becoming mostly cloudy after midnight. A slight chance of rain. Scattered thundershowers possible. Cool. Low 47°. Wind west-northwest around 4 mph, gusting to 20 mph, in the evening, becoming north after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Friday |
Partly to mostly cloudy. A chance of rain. Cool. High 59°. UV index up to 5. Wind north around 6 mph, gusting to 25 mph, in the morning, becoming 9 mph, gusting to 26 mph, in the afternoon. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch. |
| Friday night |
Partly cloudy. Cool. Low 42°. Wind north around 6 mph, gusting to 23 mph, in the evening, becoming 3 mph after midnight. |
| Saturday |
Mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. A chance of rain. Cool. High 58°. UV index up to 6. Wind north-northwest around 8 mph, gusting to 26 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Saturday night |
Clear. Cool. Low 40°. Wind north-northwest around 3 mph, gusting to 22 mph, in the evening, becoming southwest after midnight. |
| Sunday |
Sunny. High 67°. UV index up to 9. Wind south-southwest around 7 mph, gusting to 28 mph, in the morning, becoming 12 mph, gusting to 28 mph, in the afternoon. |
| Sunday night |
Clear in the evening, becoming mostly clear after midnight. Cool. Low 46°. Wind south-southwest around 9 mph, gusting to 24 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.