WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Saturday, 24-Jan-2026 05:00 am
 
Today

Snow
Snow
Tonight

Mix
Cold!
Mix
Cold!
Sunday

Snow
Cold!
Snow
Cold!
Sunday
night
Mostly Cloudy
Cold!
Mostly Cloudy
Cold!
Monday

Fog a.m.
Cold!
Fog a.m.
Cold!
Monday
night
Clear
Cold!
Clear
Cold!
Tuesday

Mostly Sunny
Cold!
Mostly Sunny
Cold!
Tuesday
night
Partly Cloudy
Partly Cloudy
<.1 in.
1 in.
<.25 in.
<3 in.
.25 in.
<5 in.
High: 4° Low: -2° High: 5° Low: -6° High: 16° Low: 5° High: 30° Low: 11°
  WCh: -15° WCh: -16° WCh: -16° WCh: -17° WCh: -10° WCh: -9°  
NNE
6-18
mph
NNE
6
mph
N
9-18
mph
NNW
7-16
mph
WNW
6-21
mph
SW
7-17→11-16
mph
SW→W
8-20
mph
W
2-16
mph

 

Today
 
Dense overcast. A slight chance of snow in the morning, then a chance of snow in the afternoon. Very cold. High 4°. Wind chill around -11. Wind north-northeast around 6 mph, gusting to 18 mph. Chance of precipitation 40 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about an inch.
Tonight
 
Dense overcast. A mix of snow and sleet likely. Very cold. Low -2°. Wind chill ranging from -15 to -9. Wind north-northeast around 6 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly less than a quarter of an inch. Snow or ice (on ground) accumulation 2 to 3 inches.
Sunday
 
Dense overcast. Snow likely in the morning, then a chance of snow in the afternoon. Very cold. High 5°. Wind chill ranging from -16 to -11. Wind north around 9 mph, gusting to 18 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. Snow accumulation 3 to 5 inches.
Sunday night
 
Partly to mostly cloudy in the evening, becoming clear after midnight. Very cold. Low -6°. Wind chill ranging from -16 to -11. Wind north-northwest around 7 mph, gusting to 16 mph.
Monday
 
Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Cold. High 16°. Wind chill ranging from -17 to 7. Wind west-northwest around 6 mph, gusting to 21 mph.
Monday night
 
Clear. Very cold. Low 5°. Wind chill ranging from -10 to 6. Wind southwest around 7 mph, gusting to 17 mph, in the evening, becoming 11 mph, gusting to 16 mph, after midnight.
Tuesday
 
Sunny in the morning, becoming partly to mostly sunny in the afternoon. High 30°. Wind chill ranging from -9 to 22. Wind southwest around 8 mph, gusting to 20 mph, in the morning, becoming west in the afternoon.
Tuesday night
 
Partly cloudy. Low 11°. Wind west around 2 mph, gusting to 16 mph.
Wednesday
 
Mostly cloudy in the morning, becoming cloudy in the afternoon. High 29°. Wind west-southwest around 3 mph, gusting to 26 mph.
Wednesday night
 
Mostly cloudy to cloudy in the evening, becoming partly to mostly cloudy after midnight. A slight chance of snow. Cold. Low 11°. Wind chill ranging from 2 to 19. Wind northwest around 8 mph, gusting to 24 mph. Chance of precipitation 20 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about a quarter inch.
Thursday
 
Mostly cloudy to cloudy. Cold. High 14°. Wind chill ranging from 1 to 6. Wind northwest around 5 mph, gusting to 20 mph.
Thursday night
 
Mostly cloudy to cloudy in the evening, becoming mostly cloudy after midnight. Cold. Low 10°. Wind north-northeast around 1 mph, gusting to 17 mph, in the evening, becoming southeast after midnight.
Friday
 
Mostly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. A slight chance of snow in the morning, then a chance of snow in the afternoon. Cold. High 22°. Wind chill around 11. Wind north-northeast around 2 mph in the morning, becoming 6 mph, gusting to 17 mph, in the afternoon. Chance of precipitation 30 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. Snow accumulation about half an inch.
Friday night
 
Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. Low 13°. Wind north-northeast near calm.

WXSIM forecast formatting script by Saratoga-Weather.org.

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