| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Saturday, 29-Aug-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Hot. High 89°. UV index up to 7. Wind south around 5 mph, gusting to 23 mph. |
| Tonight |
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 62°. Wind south around 6 mph, gusting to 18 mph. |
| Sunday |
Partly to mostly sunny. Very hot. High 94°. UV index up to 8. Wind south around 7 mph, gusting to 23 mph. |
| Sunday night |
Mostly clear in the evening, becoming clear after midnight. Low 67°. Wind south around 6 mph, gusting to 16 mph. |
| Monday |
Mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 96°. UV index up to 8. Wind south around 6 mph, gusting to 20 mph, in the morning, becoming southwest in the afternoon. |
| Monday night |
Fair in the evening, becoming mostly clear after midnight. Low 70°. Wind south around 5 mph. |
| Tuesday |
Sunny. Very hot. High 97°. Heat index up to 103°. UV index up to 8. Wind south-southwest around 6 mph, gusting to 19 mph. |
| Tuesday night |
Clear. Patchy light fog after midnight. Low 70°. Wind south around 5 mph. |
| Wednesday |
Sunny. Patchy light fog in the morning. Very hot. High 98°. Heat index up to 106°. UV index up to 8. Wind south-southwest around 6 mph, gusting to 21 mph. |
| Wednesday night |
Clear. Low 72°. Wind south around 4 mph. |
| Thursday |
Mostly sunny. Extremely hot. High 100°. Heat index up to 109°. UV index up to 8. Wind southwest around 5 mph, gusting to 20 mph. |
| Thursday night |
Partly cloudy in the evening, becoming clear after midnight. Warm. Low 74°. Wind southwest around 4 mph in the evening, becoming 8 mph after midnight. |
| Friday |
Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Extremely hot. High 100°. Heat index up to 111°. UV index up to 7. Wind south-southwest around 8 mph, gusting to 21 mph. |
| Friday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Warm. Low 77°. Wind north-northeast around 6 mph in the evening, becoming south-southwest around 2 mph after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.