| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
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| Updated: Thursday, 05-Mar-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Tonight |
Mostly cloudy to cloudy. Patchy light fog after midnight. Relatively mild. Low 53°. Wind east around 4 mph, gusting to 16 mph, in the evening, becoming south-southeast after midnight. |
| Friday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. Exceptionally hot. High 79°. UV index up to 5. Wind south around 8 mph, gusting to 23 mph, in the morning, becoming 13 mph, gusting to 30 mph, in the afternoon. |
| Friday night |
Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Scattered thundershowers possible. Breezy and unusually mild. Low 60°. Wind south around 12 mph, gusting to 25 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch. |
| Saturday |
Partly to mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Mild. High 67°. UV index up to 6. Wind west around 11 mph, gusting to 30 mph. |
| Saturday night |
Partly cloudy in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 40°. Wind west-northwest around 4 mph, gusting to 24 mph. |
| Sunday |
Partly cloudy in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Mild. High 67°. UV index up to 4. Wind west-southwest around 5 mph, gusting to 22 mph, in the morning, becoming 8 mph, gusting to 25 mph, in the afternoon. |
| Sunday night |
Clear. Low 39°. Wind west-southwest around 7 mph, gusting to 18 mph. |
| Monday |
Sunny. Unusually warm. High 75°. UV index up to 4. Wind southwest around 8 mph, gusting to 22 mph, in the morning, becoming 11 mph, gusting to 27 mph, in the afternoon. |
| Monday night |
Fair to partly cloudy. Light to moderate fog after midnight. Low 47°. Wind south-southwest around 6 mph, gusting to 19 mph. |
| Tuesday |
Mostly cloudy to cloudy in the morning, becoming cloudy in the afternoon. Light to moderate fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Scattered thunderstorms likely. Mild. High 68°. Wind south-southwest around 8 mph, gusting to 18 mph, in the morning, becoming 13 mph, gusting to 23 mph, in the afternoon. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch. |
| Tuesday night |
Dense overcast. Light to moderate fog in the evening, then patchy light fog after midnight. Rain very likely. Scattered thundershowers possible. Unusually mild. Low 59°. Wind south-southwest around 9 mph, gusting to 19 mph. Chance of precipitation 80 percent. Precipitation mostly around an inch. |
| Wednesday |
Dense overcast. Patchy light fog. Rain likely. Scattered thundershowers possible. Mild. High 60°, but temperatures falling in the afternoon. Wind west around 7 mph, gusting to 18 mph, in the morning, becoming north in the afternoon. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch. |
| Wednesday night |
Dense overcast in the evening, becoming mostly cloudy after midnight. Patchy light fog. A chance of rain. Low 41°. Wind north around 8 mph, gusting to 17 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
WXSIM forecast formatting script by Saratoga-Weather.org.