WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Tuesday, 02-Jun-2026 04:00 pm
 
Tonight

Mostly Clear
Mostly Clear
Wednesday

Mostly Sunny
Mostly Sunny
Wednesday
night
Clear
Clear
Thursday

Partly Cloudy
Partly Cloudy
Thursday
night
Partly Cloudy
Partly Cloudy
Friday

Chance rain
Chance rain
Friday
night
Chance rain
Chance rain
Saturday

Thunder storm
Thunder storm
.1 in. <.25 in. .1 in.
Low: 58° High: 83° Low: 57° High: 86° Low: 60° High: 82° Low: 66° High: 85°
               
E
5-24
mph
E
4-24
mph
ESE→S
4-20
mph
S
6-24
mph
S
7-22
mph
S
7-21
mph
SSW
4
mph
SW
8-24
mph
UV: 9
 Very High 
UV: 7
 High 
UV: 5
 Medium 
UV: 7
 High 

 

Tonight
 
Mostly clear. Relatively cool. Low 58°. Wind east around 5 mph, gusting to 24 mph.
Wednesday
 
Mostly sunny in the morning, becoming sunny in the afternoon. High 83°. UV index up to 9. Wind east around 4 mph, gusting to 24 mph.
Wednesday night
 
Clear. Relatively cool. Low 57°. Wind east-southeast around 4 mph, gusting to 20 mph, in the evening, becoming south after midnight.
Thursday
 
Mostly sunny in the morning, becoming partly cloudy in the afternoon. Hot. High 86°. UV index up to 7. Wind south around 6 mph, gusting to 24 mph.
Thursday night
 
Clear in the evening, becoming fair to partly cloudy after midnight. Relatively cool. Low 60°. Wind south around 7 mph, gusting to 22 mph.
Friday
 
Cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. A slight chance of rain in the morning, then a chance of rain in the afternoon. Precipitation showery or intermittent. High 82°. UV index up to 5. Wind south around 7 mph, gusting to 21 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Friday night
 
Partly to mostly cloudy. Light to moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Low 66°. Wind south-southwest around 4 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Saturday
 
Partly to mostly cloudy. Light to moderate fog in the morning. A chance of rain. Scattered thundershowers possible. High 85°. UV index up to 7. Wind southwest around 8 mph, gusting to 24 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Saturday night
 
Mostly cloudy to cloudy. Patchy light fog. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 70°. Wind south-southwest around 3 mph, gusting to 16 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Sunday
 
Mostly cloudy to cloudy in the morning, becoming cloudy in the afternoon. Patchy light fog in the morning, then light to moderate fog in the afternoon. A chance of rain in the morning, then rain likely in the afternoon. Scattered thundershowers possible. High 77°. UV index up to 5. Wind east-southeast around 5 mph, gusting to 16 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch.
Sunday night
 
Cloudy in the evening, becoming dense overcast after midnight. Light to moderate fog. Rain very likely. Scattered thunderstorms likely. Low 70°. Wind east-southeast around 5 mph. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch.
Monday
 
Dense overcast. Light to moderate fog. Rain very likely. Scattered thundershowers possible. High 75°. Wind east-southeast around 6 mph, gusting to 15 mph. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch.
Monday night
 
Dense overcast. Light to moderate fog in the evening, then patchy light fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Precipitation showery or intermittent. Low 71°. Wind east-southeast around 6 mph, gusting to 16 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

Powered by Davis Vantage Pro2  and   CumulusMX   v 4.6.4 (b4128)   MXUI Template v 2.2.6 by  Silver Acorn     Valid HTML5 USA Weather Finder Badge