WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Saturday, 17-Oct-2026 05:00 am
 
Today

Mostly Sunny
Mostly Sunny
Tonight

Fair
Fair
Sunday

Mostly Sunny
Mostly Sunny
Sunday
night
Clear
Clear
Monday

Sunny
Sunny
Monday
night
Clear
Clear
Tuesday

Sunny
Sunny
Tuesday
night
Partly Cloudy
Partly Cloudy
High: 62° Low: 41° High: 66° Low: 41° High: 69° Low: 43° High: 71° Low: 45°
               
NE
3-22
mph
SE
3
mph
SE
5-24
mph
SSE
4-18
mph
SSE
2-20
mph
SE
2
mph
SSE
2-21
mph
SE
2
mph
UV: 5
 Medium 
UV: 5
 Medium 
UV: 5
 Medium 
UV: 5
 Medium 

 

Today
 
Mostly sunny. High 62°. UV index up to 5. Wind northeast around 3 mph, gusting to 22 mph.
Tonight
 
Fair. Low 41°. Wind southeast around 3 mph.
Sunday
 
Mostly sunny. High 66°. UV index up to 5. Wind southeast around 5 mph, gusting to 24 mph.
Sunday night
 
Fair in the evening, becoming clear after midnight. Low 41°. Wind south-southeast around 4 mph, gusting to 18 mph.
Monday
 
Sunny. High 69°. UV index up to 5. Wind south-southeast around 2 mph, gusting to 20 mph.
Monday night
 
Clear in the evening, becoming fair after midnight. Low 43°. Wind southeast around 2 mph.
Tuesday
 
Sunny. Mild. High 71°. UV index up to 5. Wind south-southeast around 2 mph, gusting to 21 mph.
Tuesday night
 
Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 45°. Wind southeast around 2 mph.
Wednesday
 
Partly to mostly sunny in the morning, becoming sunny in the afternoon. Warm. High 73°. UV index up to 5. Wind south around 2 mph, gusting to 19 mph.
Wednesday night
 
Clear. Low 43°. Wind east-southeast around 2 mph in the evening, becoming south after midnight.
Thursday
 
Sunny. Warm. High 72°. UV index up to 4. Wind southeast around 2 mph, gusting to 17 mph.
Thursday night
 
Clear. Low 45°. Wind southeast around 3 mph.
Friday
 
Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Warm. High 75°. Wind southeast around 6 mph, gusting to 22 mph.
Friday night
 
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 50°. Wind southeast around 5 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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