WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Monday, 01-Dec-2025 04:00 pm
 
Tonight

Snow
Snow
Tuesday

Fog a.m.
Fog a.m.
Tuesday
night
Partly Cloudy
Partly Cloudy
Wednesday

Partly Cloudy
Partly Cloudy
Wednesday
night
Snow
Snow
Thursday

Mostly Sunny
Mostly Sunny
Thursday
night
Clear
Clear
Friday

Mostly Sunny
Mostly Sunny
<.1 in.
.5 in.
<.1 in.
.25 in.
Low: 15° High: 31° Low: 16° High: 42° Low: 18° High: 31° Low: 14° High: 40°
WCh: 9°       WCh: 12°      
WNW
calm→4
mph
WNW→WSW
4-19
mph
SSE
4
mph
S→WSW
4-21
mph
NNW
8-22
mph
N
4-20
mph
ENE→SE
2-16
mph
S
3-17
mph

 

Tonight
 
Dense overcast in the evening, becoming mostly cloudy after midnight. Patchy light fog. A chance of snow in the evening, then a slight chance of snow after midnight. Cold. Low 15°. Wind chill ranging from 9 to 24. Wind west-northwest near calm in the evening, becoming 4 mph after midnight. Chance of precipitation 40 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about half an inch.
Tuesday
 
Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 31°. Wind west-northwest around 4 mph, gusting to 19 mph, in the morning, becoming west-southwest in the afternoon.
Tuesday night
 
Fair to partly cloudy. Cold. Low 16°. Wind south-southeast around 4 mph.
Wednesday
 
Partly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. High 42°. Wind south around 4 mph, gusting to 21 mph, in the morning, becoming west-southwest in the afternoon.
Wednesday night
 
Dense overcast in the evening, becoming cloudy after midnight. A chance of snow in the evening, then a slight chance of snow after midnight. Cold. Low 18°. Wind chill ranging from 12 to 32. Wind north-northwest around 8 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about a quarter inch.
Thursday
 
Mostly sunny in the morning, becoming sunny in the afternoon. High 31°. Wind north around 4 mph, gusting to 20 mph.
Thursday night
 
Clear. Cold. Low 14°. Wind east-northeast around 2 mph, gusting to 16 mph, in the evening, becoming southeast after midnight.
Friday
 
Mostly sunny. High 40°. Wind south around 3 mph, gusting to 17 mph.
Friday night
 
Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Low 23°. Wind south around 4 mph in the evening, becoming west-southwest after midnight.
Saturday
 
Partly cloudy in the morning, becoming mostly cloudy in the afternoon. High 40°. Wind west around 3 mph, gusting to 16 mph, in the morning, becoming northeast in the afternoon.
Saturday night
 
Cloudy in the evening, becoming mostly cloudy after midnight. A chance of a mix of snow and rain. Low 28°. Wind chill ranging from 21 to 33. Wind east around 6 mph. Chance of precipitation 40 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about a quarter inch.
Sunday
 
Partly cloudy in the morning, becoming sunny in the afternoon. High 39°. Wind north-northeast around 7 mph, gusting to 24 mph.
Sunday night
 
Partly cloudy. Low 21°. Wind north-northeast around 1 mph, gusting to 17 mph, in the evening, becoming south-southeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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