| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Saturday, 22-Aug-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Fair. Low 65°. Wind north-northwest around 3 mph, gusting to 20 mph. |
| Sunday |
Partly cloudy. Patchy light fog in the morning. A chance of rain. High 82°. UV index up to 7. Wind north-northwest around 4 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch. |
| Sunday night |
Fair. Patchy light fog after midnight. Low 64°. Wind northeast around 3 mph in the evening, becoming east after midnight. |
| Monday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. High 83°. UV index up to 6. Wind southeast around 4 mph, gusting to 21 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Monday night |
Partly cloudy. Patchy light fog after midnight. Low 67°. Wind east around 6 mph, gusting to 20 mph. |
| Tuesday |
Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. Precipitation showery or intermittent. High 86°. UV index up to 6. Wind east-southeast around 5 mph, gusting to 23 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch. |
| Tuesday night |
Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. Low 68°. Wind east-northeast around 3 mph, gusting to 19 mph, in the evening, becoming southeast after midnight. |
| Wednesday |
Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. A chance of rain. Scattered thundershowers possible. High 85°. UV index up to 5. Wind south-southwest around 3 mph, gusting to 18 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 mostly clear after midnight. Patchy light fog after midnight. Low 66°. Wind southwest around 3 mph in the evening, becoming west-northwest after midnight. |
| Thursday |
Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. High 86°. UV index up to 7. Wind northwest around 5 mph, gusting to 22 mph. |
| Thursday night |
Clear. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 17 mph. |
| Friday |
Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 88°. UV index up to 8. Wind south around 2 mph, gusting to 18 mph, in the morning, becoming east in the afternoon. |
| Friday night |
Clear in the evening, becoming partly cloudy after midnight. Low 62°. Wind east-southeast around 6 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.