| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Monday, 28-Sep-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Sunny. Warm. High 79°. UV index up to 6. Wind east-northeast around 3 mph, gusting to 23 mph. |
| Tonight |
Clear. Low 53°. Wind east around 2 mph. |
| Tuesday |
Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Warm. High 82°. UV index up to 6. Wind south-southeast around 4 mph, gusting to 23 mph. |
| Tuesday night |
Partly cloudy. Low 58°. Wind south-southeast around 5 mph, gusting to 15 mph. |
| Wednesday |
Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Unusually hot. High 86°. UV index up to 6. Wind south-southeast around 7 mph, gusting to 20 mph. |
| Wednesday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Mild. Low 65°. Wind south-southeast around 7 mph. |
| Thursday |
Mostly cloudy to cloudy in the morning, becoming dense overcast in the afternoon. A slight chance of rain in the morning, then a chance of rain in the afternoon. Precipitation showery or intermittent. Warm. High 80°. Wind south-southeast around 5 mph, gusting to 18 mph, in the morning, becoming west-southwest in the afternoon. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch. |
| Thursday night |
Dense overcast. Patchy light fog. Rain likely. Precipitation showery or intermittent. Mild. Low 65°. Wind southeast around 3 mph in the evening, becoming north-northeast after midnight. Chance of precipitation 80 percent. Precipitation mostly around an inch. |
| Friday |
Dense overcast. Patchy light fog. Rain likely in the morning, then a chance of rain in the afternoon. Precipitation showery or intermittent. High 68°. Wind northeast around 4 mph, gusting to 16 mph, in the morning, becoming 9 mph, gusting to 23 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch. |
| Friday night |
Mostly cloudy to cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain. Low 58°. Wind northeast around 7 mph, gusting to 22 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Saturday |
Partly to mostly cloudy. Light to moderate fog in the morning. High 72°. UV index up to 4. Wind northeast around 5 mph, gusting to 22 mph. |
| Saturday night |
Mostly cloudy in the evening, becoming cloudy after midnight. Low 59°. Wind east-northeast around 2 mph, gusting to 18 mph, in the evening, becoming west-northwest after midnight. |
| Sunday |
Cloudy in the morning, becoming partly to mostly sunny in the afternoon. High 72°. UV index up to 4. Wind north-northwest around 4 mph in the morning, becoming 8 mph, gusting to 20 mph, in the afternoon. |
| Sunday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Low 56°. Wind north-northwest around 6 mph, gusting to 17 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.