| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Saturday, 07-Mar-2026 03:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Partly cloudy in the evening, becoming fair after midnight. Low 38°. Wind west-northwest around 5 mph. |
| Sunday |
Mostly sunny. Mild. High 67°. UV index up to 5. Wind west-southwest around 8 mph, gusting to 26 mph. |
| Sunday night |
Fair. Low 42°. Wind west-southwest around 7 mph, gusting to 20 mph. |
| Monday |
Mostly sunny in the morning, becoming sunny in the afternoon. Exceptionally hot. High 80°. UV index up to 4. Wind south-southwest around 8 mph, gusting to 24 mph, in the morning, becoming 11 mph, gusting to 28 mph, in the afternoon. |
| Monday night |
Mostly clear in the evening, becoming fair after midnight. Relatively mild. Low 55°. Wind south-southwest around 8 mph, gusting to 21 mph. |
| Tuesday |
Mostly cloudy in the morning, becoming cloudy in the afternoon. Patchy light fog in the afternoon. A slight chance of rain in the morning, then rain likely in the afternoon. Thunderstorms very likely, some severe. Exceptionally hot. High 81°. Wind south-southwest around 8 mph, gusting to 23 mph, in the morning, becoming 12 mph, gusting to 28 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch. |
| Tuesday night |
Cloudy. Patchy light fog in the evening, then light to moderate fog after midnight. Rain very likely. Thunderstorms very likely, some severe. Breezy and unusually warm. Low 62°. Wind south-southwest around 12 mph, gusting to 27 mph. Chance of precipitation 90 percent. Precipitation mostly around an inch. |
| Wednesday |
Dense overcast in the morning, becoming cloudy in the afternoon. Light to moderate fog in the morning, then patchy light fog in the afternoon. Rain likely in the morning, then a slight chance of rain in the afternoon. Thunderstorms very likely, some possibly severe. Breezy and mild. High 64°, but temperatures falling in the afternoon. Wind west around 14 mph, gusting to 33 mph. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch. |
| Wednesday night |
Partly cloudy in the evening, becoming mostly clear after midnight. Light to moderate fog in the evening, then moderate fog after midnight. Low 35°. Wind west-northwest around 10 mph, gusting to 29 mph. |
| Thursday |
Sunny. Moderate fog in the morning, then patchy light fog in the afternoon. High 53°. Wind west-southwest around 7 mph, gusting to 16 mph, in the morning, becoming 11 mph, gusting to 24 mph, in the afternoon. |
| Thursday night |
Fair. Breezy. Low 42°. Wind west-southwest around 14 mph, gusting to 22 mph. |
| Friday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Breezy and mild. High 65°. Wind west-southwest around 13 mph, gusting to 29 mph. |
| Friday night |
Partly cloudy in the evening, becoming mostly cloudy after midnight. Low 39°. Wind north around 7 mph, gusting to 18 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.