| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Friday, 21-Aug-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Mostly sunny. Hot. High 88°. UV index up to 8. Wind south-southwest around 3 mph, gusting to 21 mph. |
| Tonight |
Fair to partly cloudy. Patchy light fog after midnight. A chance of rain. Low 65°. Wind west-southwest near calm. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Saturday |
Mostly sunny. Patchy light fog in the morning. High 86°. UV index up to 7. Wind north-northwest around 5 mph, gusting to 22 mph. |
| Saturday night |
Fair in the evening, becoming mostly clear after midnight. Low 64°. Wind north-northwest around 3 mph, gusting to 16 mph. |
| Sunday |
Partly cloudy. High 85°. UV index up to 7. Wind north-northwest around 3 mph, gusting to 22 mph. |
| Sunday night |
Partly cloudy in the evening, becoming fair after midnight. Low 63°. Wind east-northeast around 2 mph, gusting to 18 mph. |
| Monday |
Partly cloudy in the morning, becoming mostly cloudy in the afternoon. High 84°. UV index up to 6. Wind east-southeast around 4 mph, gusting to 22 mph. |
| Monday night |
Fair in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 63°. Wind east-southeast around 4 mph, gusting to 19 mph. |
| Tuesday |
Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. High 85°. UV index up to 7. Wind east-southeast around 5 mph, gusting to 21 mph. |
| Tuesday night |
Mostly clear in the evening, becoming partly to mostly cloudy after midnight. Low 65°. Wind east-southeast around 3 mph, gusting to 19 mph. |
| Wednesday |
Mostly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. A chance of rain. Scattered thundershowers possible. High 86°. UV index up to 7. Wind south-southeast around 3 mph, gusting to 16 mph, in the morning, becoming west in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Wednesday night |
Fair in the evening, becoming clear after midnight. Light to moderate fog after midnight. Low 66°. Wind west-northwest around 3 mph. |
| Thursday |
Sunny. Light to moderate fog in the morning. Hot. High 87°. UV index up to 8. Wind northwest around 6 mph, gusting to 20 mph. |
| Thursday night |
Mostly clear in the evening, becoming mostly cloudy after midnight. Low 66°. Wind north-northeast around 3 mph in the evening, becoming east after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.