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: Tuesday, 17-Mar-2026 04:00 pm

Tonight Mostly Cloudy	Wednesday Mostly Sunny	Wednesday night Mostly Cloudy	Thursday Partly Cloudy	Thursday night Clear	Friday Sunny	Friday night Partly Cloudy	Saturday Sunny

Low: 30°	High: 63°	Low: 40°	High: 70°	Low: 39°	High: 76°	Low: 45°	High: 83°
WCh: 23°
SE 6-22→9-21 mph	S→WSW 7-25 mph	NW→S 2-21 mph	S 3-20 mph	ENE→S 2-17 mph	WSW 3→7-22 mph	WSW→WNW 4 mph	SSW 4-22 mph
	UV: 4 Medium		UV: 5 Medium		UV: 6 High		UV: 6 High

Tonight	Cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Cold. Low 30°, but temperatures rising after midnight. Wind chill ranging from 23 to 29. Wind southeast around 6 mph, gusting to 22 mph, in the evening, becoming 9 mph, gusting to 21 mph, after midnight.
Wednesday	Partly to mostly sunny. Mild. High 63°. UV index up to 4. Wind south around 7 mph, gusting to 25 mph, in the morning, becoming west-southwest in the afternoon.
Wednesday night	Partly to mostly cloudy. Low 40°. Wind northwest around 2 mph, gusting to 21 mph, in the evening, becoming south after midnight.
Thursday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Mild. High 70°. UV index up to 5. Wind south around 3 mph, gusting to 20 mph.
Thursday night	Clear in the evening, becoming fair after midnight. Low 39°. Wind east-northeast around 2 mph, gusting to 17 mph, in the evening, becoming south after midnight.
Friday	Sunny. Unusually warm. High 76°. UV index up to 6. Wind west-southwest around 3 mph in the morning, becoming 7 mph, gusting to 22 mph, in the afternoon.
Friday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 45°. Wind west-southwest around 4 mph in the evening, becoming west-northwest after midnight.
Saturday	Sunny. Exceptionally hot. High 83°. UV index up to 6. Wind south-southwest around 4 mph, gusting to 22 mph.
Saturday night	Clear. Low 46°. Wind south-southwest around 5 mph.
Sunday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Mild. High 71°. UV index up to 6. Wind north around 11 mph, gusting to 30 mph.
Sunday night	Fair in the evening, becoming partly cloudy after midnight. Low 40°. Wind north-northeast around 10 mph, gusting to 26 mph.
Monday	Mostly cloudy. Breezy. High 55°. UV index up to 4. Wind north-northeast around 11 mph, gusting to 29 mph.
Monday night	Partly cloudy in the evening, becoming mostly clear after midnight. Low 35°. Wind north-northeast around 6 mph, gusting to 26 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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