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: Wednesday, 18-Mar-2026 04:00 pm

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

Low: 45°	High: 75°	Low: 45°	High: 80°	Low: 45°	High: 80°	Low: 50°	High: 82°

WNW→SSW 2-27 mph	SSW→SSE 3-20 mph	SE→SSW 3 mph	SW 4-16→8-23 mph	WNW→NNW 2-16 mph	S→WSW calm→4-21 4	SSW 4→7 mph	SSW→NW 8-26→13-30 mph
	UV: 5 Medium		UV: 5 Medium		UV: 6 High		UV: 5 Medium

Tonight	Partly cloudy. Low 45°. Wind west-northwest around 2 mph, gusting to 27 mph, in the evening, becoming south-southwest after midnight.
Thursday	Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Unusually warm. High 75°. UV index up to 5. Wind south-southwest around 3 mph, gusting to 20 mph, in the morning, becoming south-southeast in the afternoon.
Thursday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 45°. Wind southeast around 3 mph in the evening, becoming south-southwest after midnight.
Friday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Unusually warm. High 80°. UV index up to 5. Wind southwest around 4 mph, gusting to 16 mph, in the morning, becoming 8 mph, gusting to 23 mph, in the afternoon.
Friday night	Partly cloudy. Low 45°. Wind west-northwest around 2 mph, gusting to 16 mph, in the evening, becoming north-northwest after midnight.
Saturday	Sunny. Unusually warm. High 80°. UV index up to 6. Wind south near calm in the morning, becoming west-southwest around 4 mph, gusting to 21 mph, in the afternoon.
Saturday night	Clear. Low 50°. Wind south-southwest around 4 mph in the evening, becoming 7 mph after midnight.
Sunday	Sunny in the morning, becoming partly cloudy in the afternoon. Unusually hot. High 82°. UV index up to 5. Wind south-southwest around 8 mph, gusting to 26 mph, in the morning, becoming northwest around 13 mph, gusting to 30 mph, in the afternoon.
Sunday night	Fair in the evening, becoming fair to partly cloudy after midnight. Breezy. Low 39°. Wind north-northwest around 11 mph, gusting to 27 mph.
Monday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. High 60°. UV index up to 6. Wind north around 7 mph, gusting to 27 mph.
Monday night	Mostly clear in the evening, becoming partly cloudy after midnight. Low 37°. Wind east-southeast around 4 mph, gusting to 22 mph.
Tuesday	Partly to mostly cloudy in the morning, becoming mostly cloudy in the afternoon. High 60°. UV index up to 5. Wind south-southeast around 7 mph, gusting to 27 mph.
Tuesday night	Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Low 41°. Wind south-southeast around 4 mph, gusting to 23 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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