| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Thursday, 18-Jun-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. High 88°. UV index up to 7. Wind west-northwest around 6 mph, gusting to 27 mph. |
| Tonight |
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Relatively cool. Low 64°. Wind west-northwest around 3 mph, gusting to 25 mph. |
| Friday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. High 85°. UV index up to 8. Wind northwest around 4 mph, gusting to 24 mph. |
| Friday night |
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Relatively cool. Low 63°. Wind east around 3 mph, gusting to 18 mph, in the evening, becoming south after midnight. |
| Saturday |
Sunny in the morning, becoming partly cloudy in the afternoon. Hot. High 89°. UV index up to 8. Wind northwest around 4 mph, gusting to 24 mph. |
| Saturday night |
Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 65°. Wind east around 5 mph, gusting to 19 mph. |
| Sunday |
Dense overcast in the morning, becoming mostly cloudy to cloudy in the afternoon. Patchy light fog. Rain very likely. Thunderstorms very likely, some severe. High 76°. UV index up to 5. Wind east-southeast around 6 mph, gusting to 16 mph, in the morning, becoming south in the afternoon. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch. |
| Sunday night |
Cloudy. Light to moderate fog. Rain likely in the evening, then a chance of rain after midnight. Thunderstorms very likely, some severe. Low 70°. Wind southwest around 7 mph, gusting to 19 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch. |
| Monday |
Cloudy. A chance of rain. Scattered thunderstorms likely. High 79°. UV index up to 5. Wind north around 7 mph, gusting to 24 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Monday night |
Mostly cloudy to cloudy. Low 66°. Wind northeast around 4 mph, gusting to 21 mph. |
| Tuesday |
Mostly cloudy. High 82°. UV index up to 5. Wind east around 4 mph, gusting to 22 mph. |
| Tuesday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Relatively cool. Low 65°. Wind north around 5 mph, gusting to 19 mph. |
| Wednesday |
Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. A chance of rain. High 78°. UV index up to 9. Wind north around 6 mph, gusting to 26 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Wednesday night |
Clear. Patchy light fog after midnight. Relatively cool. Low 61°. Wind north-northeast around 3 mph, gusting to 20 mph, in the evening, becoming east after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.