WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Thursday, 15-Oct-2026 05:00 am
 
Today

Rain likely
Rain likely
Tonight

Chance rain
Chance rain
Friday

Partly Cloudy
Partly Cloudy
Friday
night
Partly Cloudy
Partly Cloudy
Saturday

Sunny
Sunny
Saturday
night
Clear
Clear
Sunday

Sunny
Sunny
Sunday
night
Clear
Clear
.35 in. .1 in. <.1 in.
High: 76° Low: 55° High: 57° Low: 42° High: 62° Low: 41° High: 68° Low: 44°
               
SSW
3-16→8-22
mph
WNW
11-28
mph
NW
14-31
mph
NW
12-27→8-21
mph
N
4-24
mph
ESE→SSE
2
mph
SSE
5-25
mph
SSE
3-18
mph
UV: 4
 Medium 
UV: 5
 Medium 

 

Today
 
Dense overcast in the morning, becoming cloudy in the afternoon. Rain likely. Warm. High 76°. Wind south-southwest around 3 mph, gusting to 16 mph, in the morning, becoming 8 mph, gusting to 22 mph, in the afternoon. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch.
Tonight
 
Mostly cloudy in the evening, becoming partly to mostly cloudy after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Breezy. Low 55°. Wind west-northwest around 11 mph, gusting to 28 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Friday
 
Partly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. A slight chance of rain. Breezy. High 57°, but temperatures falling in the afternoon. Wind northwest around 14 mph, gusting to 31 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Friday night
 
Partly cloudy in the evening, becoming fair after midnight. Low 42°. Wind northwest around 12 mph, gusting to 27 mph, in the evening, becoming 8 mph, gusting to 21 mph, after midnight.
Saturday
 
Sunny. High 62°. UV index up to 4. Wind north around 4 mph, gusting to 24 mph.
Saturday night
 
Clear. Low 41°. Wind east-southeast around 2 mph in the evening, becoming south-southeast after midnight.
Sunday
 
Sunny. High 68°. UV index up to 5. Wind south-southeast around 5 mph, gusting to 25 mph.
Sunday night
 
Clear. Low 44°. Wind south-southeast around 3 mph, gusting to 18 mph.
Monday
 
Sunny in the morning, becoming partly to mostly sunny in the afternoon. Mild. High 71°. Wind south-southeast around 3 mph, gusting to 23 mph.
Monday night
 
Partly cloudy. Low 45°. Wind south-southeast around 2 mph.
Tuesday
 
Partly to mostly sunny. Mild. High 72°. UV index up to 4. Wind southeast around 3 mph, gusting to 19 mph.
Tuesday night
 
Mostly cloudy in the evening, becoming fair after midnight. Low 46°. Wind east-southeast around 2 mph.
Wednesday
 
Sunny. Warm. High 73°. Wind southeast around 4 mph, gusting to 20 mph.
Wednesday night
 
Clear in the evening, becoming fair to partly cloudy after midnight. Low 47°. Wind southeast around 3 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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