OFallon Missouri Weather

OFallon - Weather Data from OFallon, MO

Latitude: N 38° 50' 20" Longitude: W 90° 43' 42" Altitude: 532 ft

CDT UTC Last station update CDT

WXSIM Forecast for: O'Fallon
Issued by: OFallonweather.com

Updated: Monday, 16-Mar-2026 04:00 pm

Tonight Partly Cloudy	Tuesday Mostly Cloudy	Tuesday night Mix	Wednesday Partly Cloudy	Wednesday night Partly Cloudy	Thursday Mostly Sunny	Thursday night Clear	Friday Mostly Sunny
		<.1 in.
Low: 17°	High: 39°	Low: 32°	High: 64°	Low: 39°	High: 72°	Low: 39°	High: 77°
WCh: 7°		WCh: 25°
WNW 11-30 mph	WNW→SW 5-24 mph	SE 8-22 mph	S→WSW 7-24 mph	NNW→SSE 2-20 mph	SSE 3-19 mph	SE→SW 2 mph	SW 2→5-22 mph
			UV: 4 Medium		UV: 5 Medium		UV: 5 Medium

Tonight	Partly cloudy in the evening, becoming fair after midnight. Very cold. Low 17°. Wind chill ranging from 7 to 14. Wind west-northwest around 11 mph, gusting to 30 mph.
Tuesday	Partly to mostly sunny in the morning, becoming mostly cloudy in the afternoon. Cold. High 39°. Wind west-northwest around 5 mph, gusting to 24 mph, in the morning, becoming southwest in the afternoon.
Tuesday night	Cloudy. A slight chance of snow in the evening, then a slight chance of a mix of snow, rain, and sleet after midnight. Cold. Low 32°. Wind chill ranging from 25 to 33. Wind southeast around 8 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. No snow or ice (on ground) accumulation expected.
Wednesday	Partly cloudy in the morning, becoming mostly sunny in the afternoon. Mild. High 64°. UV index up to 4. Wind south around 7 mph, gusting to 24 mph, in the morning, becoming west-southwest in the afternoon.
Wednesday night	Partly cloudy in the evening, becoming mostly cloudy after midnight. Low 39°. Wind north-northwest around 2 mph, gusting to 20 mph, in the evening, becoming south-southeast after midnight.
Thursday	Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Mild. High 72°. UV index up to 5. Wind south-southeast around 3 mph, gusting to 19 mph.
Thursday night	Clear in the evening, becoming fair after midnight. Low 39°. Wind southeast around 2 mph in the evening, becoming southwest after midnight.
Friday	Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Unusually warm. High 77°. UV index up to 5. Wind southwest around 2 mph in the morning, becoming 5 mph, gusting to 22 mph, in the afternoon.
Friday night	Clear in the evening, becoming fair to partly cloudy after midnight. Low 46°. Wind west around 5 mph.
Saturday	Mostly sunny in the morning, becoming sunny in the afternoon. Exceptionally hot. High 85°. UV index up to 6. Wind west-southwest around 4 mph, gusting to 23 mph.
Saturday night	Clear in the evening, becoming fair after midnight. Low 46°. Wind southwest around 3 mph.
Sunday	Partly to mostly sunny in the morning, becoming mostly cloudy in the afternoon. Breezy and mild. High 69°. UV index up to 5. Wind north-northwest around 11 mph, gusting to 32 mph, in the morning, becoming 15 mph, gusting to 33 mph, in the afternoon.
Sunday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 38°. Wind chill ranging from 33 to 60. Wind north-northeast around 11 mph, gusting to 28 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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