| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Thursday, 04-Jun-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Today |
Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. High 85°. UV index up to 7. Wind south-southeast around 6 mph, gusting to 24 mph. |
| Tonight |
Fair in the evening, becoming partly to mostly cloudy after midnight. Low 62°. Wind south-southeast around 8 mph, gusting to 20 mph. |
| Friday |
Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Hot. High 86°. UV index up to 8. Wind south around 9 mph, gusting to 27 mph, in the morning, becoming southwest in the afternoon. |
| Friday night |
Partly to mostly cloudy. Moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Scattered thunderstorms likely. Low 68°. Wind southwest around 8 mph, gusting to 23 mph. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch. |
| Saturday |
Partly cloudy in the morning, becoming mostly cloudy in the afternoon. Moderate to dense fog in the morning. Hot. High 86°. UV index up to 6. Wind southwest around 6 mph, gusting to 22 mph. |
| Saturday night |
Mostly cloudy. Light to moderate fog after midnight. A chance of rain. Scattered thunderstorms likely, some possibly severe. Low 70°. Wind southwest around 3 mph, gusting to 19 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Sunday |
Mostly cloudy to cloudy. Patchy light fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Thunderstorms very likely, some possibly severe. High 86°. UV index up to 8. Wind south-southeast around 4 mph, gusting to 19 mph, in the morning, becoming 8 mph, gusting to 24 mph, in the afternoon. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch. |
| Sunday night |
Cloudy in the evening, becoming dense overcast after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain. Thunderstorms very likely, some severe. Low 73°. Wind south around 6 mph, gusting to 18 mph. Chance of precipitation 50 percent. Precipitation mostly less than a tenth of an inch. |
| Monday |
Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. Light to moderate fog. Rain likely. Thunderstorms very likely, some possibly severe. High 79°. UV index up to 8. Wind south around 6 mph, gusting to 19 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch. |
| Monday night |
Mostly cloudy. Light to moderate fog in the evening, then moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Thunderstorms very likely, some possibly severe. Low 71°. Wind south around 6 mph, gusting to 16 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch. |
| Tuesday |
Partly to mostly cloudy. Moderate fog in the morning. A chance of rain. Scattered thunderstorms likely, some possibly severe. Hot. High 87°. Heat index up to 94°. UV index up to 7. Wind south around 5 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Tuesday night |
Fair. Light to moderate fog in the evening, then moderate fog after midnight. Low 71°. Wind south around 4 mph, gusting to 19 mph. |
| Wednesday |
Partly to mostly sunny. Light to moderate fog in the morning. Hot. High 92°. Heat index up to 102°. UV index up to 9. Wind south-southwest around 4 mph, gusting to 21 mph. |
| Wednesday night |
Fair in the evening, becoming mostly cloudy to cloudy after midnight. Patchy light fog in the evening, then moderate fog after midnight. A chance of rain. Scattered thunderstorms likely, some possibly severe. Low 74°. Wind south-southwest around 4 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
WXSIM forecast formatting script by Saratoga-Weather.org.