WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com
Updated: Monday, 26-Oct-2026 04:00 pm
 
Tonight

Partly Cloudy
Partly Cloudy
Tuesday

Mostly Cloudy
Mostly Cloudy
Tuesday
night
Partly Cloudy
Partly Cloudy
Wednesday

Partly Cloudy
Partly Cloudy
Wednesday
night
Clear
Clear
Thursday

Partly Cloudy
Partly Cloudy
Thursday
night
Mostly Cloudy
Mostly Cloudy
Friday

Mostly Cloudy
Mostly Cloudy
Low: 52° High: 74° Low: 54° High: 75° Low: 48° High: 78° Low: 54° High: 74°
               
SE→S
3-17
mph
S
4-22
mph
SSE
4-17
mph
S
5-21
mph
S
6
mph
S→WSW
6-22
mph
NNW→NE
2
mph
ESE
4-17
mph

 

Tonight
 
Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 52°. Wind southeast around 3 mph, gusting to 17 mph, in the evening, becoming south after midnight.
Tuesday
 
Partly to mostly cloudy. Warm. High 74°. Wind south around 4 mph, gusting to 22 mph.
Tuesday night
 
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 54°. Wind south-southeast around 4 mph, gusting to 17 mph.
Wednesday
 
Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Warm. High 75°. Wind south around 5 mph, gusting to 21 mph.
Wednesday night
 
Clear. Low 48°. Wind south around 6 mph.
Thursday
 
Sunny in the morning, becoming partly cloudy in the afternoon. Unusually warm. High 78°. Wind south around 6 mph, gusting to 22 mph, in the morning, becoming west-southwest in the afternoon.
Thursday night
 
Mostly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 54°. Wind north-northwest around 2 mph in the evening, becoming northeast after midnight.
Friday
 
Mostly cloudy. Warm. High 74°. Wind east-southeast around 4 mph, gusting to 17 mph.
Friday night
 
Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Low 53°. Wind south-southeast around 3 mph.
Saturday
 
Mostly cloudy to cloudy. A chance of rain. Mild. High 70°. Wind southeast around 4 mph, gusting to 16 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday night
 
Cloudy in the evening, becoming dense overcast after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Mild. Low 59°. Wind east-southeast around 6 mph, gusting to 15 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch.
Sunday
 
Mostly cloudy in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Mild. High 72°. Wind northwest around 5 mph, gusting to 22 mph.
Sunday night
 
Cloudy. Mild. Low 57°. Wind north around 3 mph, gusting to 15 mph, in the evening, becoming east-northeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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