WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Thursday, 27-Nov-2025 05:00 am
 
Today

Sunny
Sunny
Tonight

Mostly Clear
Mostly Clear
Friday

Partly Cloudy
Partly Cloudy
Friday
night
Freezing Rain
Freezing Rain
Saturday

Freezing Rain
Freezing Rain
Saturday
night
Freezing Rain
Freezing Rain
Sunday

Mostly Cloudy
Mostly Cloudy
Sunday
night
Mostly Cloudy
Mostly Cloudy
.1 in.
.5 in.
.75 in.
<3 in.
<.25 in.
.25 in.
High: 41° Low: 20° High: 42° Low: 30° High: 33° Low: 28° High: 30° Low: 19°
      WCh: 25°   WCh: 19°    
NW
8-26
mph
NW
5-19
mph
NNW→SSW
2-17
mph
ESE
4-17→7-17
mph
ESE
10-21
mph
SSW→W
9-20→13-25
mph
W
10-26
mph
NNW
4-20
mph

 

Today
 
Sunny. High 41°. Wind northwest around 8 mph, gusting to 26 mph.
Tonight
 
Clear in the evening, becoming mostly clear after midnight. Low 20°. Wind northwest around 5 mph, gusting to 19 mph.
Friday
 
Sunny in the morning, becoming partly cloudy in the afternoon. High 42°. Wind north-northwest around 2 mph, gusting to 17 mph, in the morning, becoming south-southwest in the afternoon.
Friday night
 
Cloudy in the evening, becoming dense overcast after midnight. A slight chance of snow in the evening, then a chance of a mix of snow, freezing rain, and sleet after midnight. Low 30°. Wind chill ranging from 25 to 38. Wind east-southeast around 4 mph, gusting to 17 mph, in the evening, becoming 7 mph, gusting to 17 mph, after midnight. Chance of precipitation 50 percent. Precipitation (liquid equivalent) mostly around a tenth of an inch. Snow or ice (on ground) accumulation about half an inch. Little if any freezing rain accumulation.
Saturday
 
Dense overcast. Patchy light fog in the afternoon. Snow likely in the morning, then a mix of snow, sleet, and freezing rain likely in the afternoon. High 33°. Wind chill around 22. Wind east-southeast around 10 mph, gusting to 21 mph. Chance of precipitation 80 percent. Precipitation (liquid equivalent) mostly between half an inch and one inch. Snow or ice (on ground) accumulation 2 to 3 inches. Little if any freezing rain accumulation.
Saturday night
 
Cloudy. Patchy light fog in the evening. A chance of a mix of snow, sleet, rain, and freezing rain in the evening, then a chance of snow after midnight. Low 28°. Wind chill ranging from 19 to 26. Wind south-southwest around 9 mph, gusting to 20 mph, in the evening, becoming west around 13 mph, gusting to 25 mph, after midnight. Chance of precipitation 60 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow or ice (on ground) accumulation about a quarter inch. Little if any freezing rain accumulation.
Sunday
 
Mostly cloudy to cloudy in the morning, becoming cloudy in the afternoon. Cold. High 30°. Wind chill around 20. Wind west around 10 mph, gusting to 26 mph.
Sunday night
 
Mostly cloudy. Cold. Low 19°. Wind north-northwest around 4 mph, gusting to 20 mph.
Monday
 
Cloudy. A slight chance of snow. Cold. High 28°. Wind northeast around 2 mph, gusting to 17 mph. Chance of precipitation 20 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Little or no snow accumulation expected.
Monday night
 
Cloudy in the evening, becoming mostly cloudy after midnight. A slight chance of snow. Low 21°. Wind northeast around 3 mph, gusting to 16 mph. Chance of precipitation 20 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Little or no snow accumulation expected.
Tuesday
 
Mostly cloudy in the morning, becoming cloudy in the afternoon. A slight chance of snow in the morning, then a chance of snow in the afternoon. Cold. High 29°. Wind north around 4 mph. Chance of precipitation 40 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about half an inch.
Tuesday night
 
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Cold. Low 19°. Wind chill ranging from 13 to 22. Wind south around 4 mph.
Wednesday
 
Mostly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. Patchy light fog in the morning. High 40°. Wind south-southeast around 7 mph, gusting to 16 mph.
Wednesday night
 
Mostly cloudy to cloudy in the evening, becoming cloudy after midnight. Low 30°. Wind chill ranging from 23 to 31. Wind south-southwest around 7 mph, gusting to 16 mph, in the evening, becoming west-northwest after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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