WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Friday, 24-Apr-2026 05:00 am
 
Today

Thunder storm
Thunder storm
Tonight

Fog late
Fog late
Saturday

Fog a.m.
Fog a.m.
Saturday
night
Fog late
Fog late
Sunday

Fog a.m.
Fog a.m.
Sunday
night
Partly Cloudy
Partly Cloudy
Monday

Thunder storm
Thunder storm
Monday
night
Thunder storm
Thunder storm
.1 in. <.25 in. <.1 in.
High: 76° Low: 52° High: 75° Low: 50° High: 76° Low: 54° High: 78° Low: 57°
               
S→NW
5-22
mph
NNW
5-19
mph
NE
7-25
mph
NE
5-20
mph
ESE
7-26→10-27
mph
ESE
9-23
mph
SSE
13-31→18-31
mph
WSW
12-26→8-17
mph
UV: 4
 Medium 
UV: 6
 High 
UV: 7
 High 
UV: 5
 Medium 

 

Today
 
Mostly cloudy to cloudy. Patchy light fog in the morning. A chance of rain. Thunderstorms very likely, some possibly severe. Warm. High 76°. UV index up to 4. Wind south around 5 mph, gusting to 22 mph, in the morning, becoming northwest in the afternoon. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Tonight
 
Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 52°. Wind north-northwest around 5 mph, gusting to 19 mph.
Saturday
 
Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 75°. UV index up to 6. Wind northeast around 7 mph, gusting to 25 mph.
Saturday night
 
Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 50°. Wind northeast around 5 mph, gusting to 20 mph.
Sunday
 
Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Warm. High 76°. UV index up to 7. Wind east-southeast around 7 mph, gusting to 26 mph, in the morning, becoming 10 mph, gusting to 27 mph, in the afternoon.
Sunday night
 
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 54°. Wind east-southeast around 9 mph, gusting to 23 mph.
Monday
 
Partly cloudy in the morning, becoming mostly cloudy in the afternoon. A slight chance of rain in the morning, then a chance of rain in the afternoon. Thunderstorms very likely, some possibly severe. Breezy and warm. High 78°. UV index up to 5. Wind south-southeast around 13 mph, gusting to 31 mph, in the morning, becoming 18 mph, gusting to 31 mph, in the afternoon. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Monday night
 
Fair to partly cloudy. Patchy light fog. A slight chance of rain. Scattered thundershowers possible. Low 57°. Wind west-southwest around 12 mph, gusting to 26 mph, in the evening, becoming 8 mph, gusting to 17 mph, after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday
 
Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 74°. UV index up to 7. Wind west-northwest around 8 mph, gusting to 27 mph.
Tuesday night
 
Fair to partly cloudy in the evening, becoming mostly clear after midnight. Low 49°. Wind northwest around 5 mph, gusting to 23 mph.
Wednesday
 
Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. High 73°. UV index up to 7. Wind north around 7 mph, gusting to 27 mph.
Wednesday night
 
Partly cloudy in the evening, becoming clear after midnight. Low 48°. Wind north-northeast around 3 mph, gusting to 23 mph.
Thursday
 
Partly to mostly cloudy in the morning, becoming cloudy in the afternoon. High 65°. UV index up to 5. Wind north around 4 mph, gusting to 24 mph, in the morning, becoming 8 mph, gusting to 24 mph, in the afternoon.
Thursday night
 
Fair to partly cloudy in the evening, becoming mostly clear after midnight. Cool. Low 46°. Wind north around 5 mph, gusting to 22 mph, in the evening, becoming east-northeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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