WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Monday, 19-Oct-2026 05:00 am
 
Today

Mostly Sunny
Mostly Sunny
Tonight

Partly Cloudy
Partly Cloudy
Tuesday

Mostly Sunny
Mostly Sunny
Tuesday
night
Clear
Clear
Wednesday

Sunny
Sunny
Wednesday
night
Clear
Clear
Thursday

Sunny
Sunny
Thursday
night
Clear
Clear
High: 69° Low: 44° High: 71° Low: 43° High: 71° Low: 43° High: 72° Low: 45°
               
SSE
2-20
mph
ESE
2
mph
SE
2-19
mph
E→SSE
2
mph
SSE→E
1-22
mph
ESE→S
calm

ESE
2-20
mph
ESE
2
mph
UV: 5
 Medium 
UV: 4
 Medium 
UV: 5
 Medium 
UV: 4
 Medium 

 

Today
 
Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. High 69°. UV index up to 5. Wind south-southeast around 2 mph, gusting to 20 mph.
Tonight
 
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 44°. Wind east-southeast around 2 mph.
Tuesday
 
Mostly sunny. Mild. High 71°. UV index up to 4. Wind southeast around 2 mph, gusting to 19 mph.
Tuesday night
 
Fair in the evening, becoming clear after midnight. Low 43°. Wind east around 2 mph in the evening, becoming south-southeast after midnight.
Wednesday
 
Sunny. Mild. High 71°. UV index up to 5. Wind south-southeast around 1 mph, gusting to 22 mph, in the morning, becoming east in the afternoon.
Wednesday night
 
Clear. Low 43°. Wind east-southeast near calm in the evening, becoming south after midnight.
Thursday
 
Sunny. Warm. High 72°. UV index up to 4. Wind east-southeast around 2 mph, gusting to 20 mph.
Thursday night
 
Clear. Low 45°. Wind east-southeast around 2 mph.
Friday
 
Sunny. Warm. High 74°. UV index up to 5. Wind southeast around 4 mph, gusting to 23 mph.
Friday night
 
Clear in the evening, becoming partly cloudy after midnight. Low 49°. Wind southeast around 4 mph.
Saturday
 
Partly cloudy. Warm. High 76°. UV index up to 4. Wind southeast around 5 mph, gusting to 24 mph.
Saturday night
 
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 51°. Wind south around 6 mph, gusting to 16 mph.
Sunday
 
Mostly cloudy. Warm. High 74°. Wind south around 8 mph, gusting to 22 mph, in the morning, becoming west-southwest in the afternoon.
Sunday night
 
Partly cloudy in the evening, becoming cloudy after midnight. Low 53°. Wind west-southwest near calm in the evening, becoming east-southeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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