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: Thursday, 03-Sep-2026 04:00 pm

Tonight Clear	Friday Sunny Hot!	Friday night Mostly Clear	Saturday Mostly Sunny Hot!	Saturday night Clear	Sunday Fog a.m.	Sunday night Partly Cloudy	Monday Partly Cloudy

Low: 74°	High: 98°	Low: 73°	High: 96°	Low: 70°	High: 92°	Low: 67°	High: 90°
	Heat: 107°		Heat: 104°		Heat: 97°
S 5-22 mph	SSW 5-24 mph	S 3 mph	W→NNW 4-19 mph	NE 3 mph	NE 5-24 mph	ENE 6-19 mph	E 5-24 mph
	UV: 7 High		UV: 6 High		UV: 7 High		UV: 8 Very High

Tonight	Fair in the evening, becoming clear after midnight. Warm. Low 74°. Wind south around 5 mph, gusting to 22 mph.
Friday	Sunny. Extremely hot. High 98°. Heat index up to 107°. UV index up to 7. Wind south-southwest around 5 mph, gusting to 24 mph.
Friday night	Mostly clear in the evening, becoming fair after midnight. Warm. Low 73°. Wind south around 3 mph.
Saturday	Partly to mostly sunny. Very hot. High 96°. Heat index up to 104°. UV index up to 6. Wind west around 4 mph, gusting to 19 mph, in the morning, becoming north-northwest in the afternoon.
Saturday night	Fair in the evening, becoming clear after midnight. Low 70°. Wind northeast around 3 mph.
Sunday	Sunny. Patchy light fog in the morning. Very hot. High 92°. Heat index up to 97°. UV index up to 7. Wind northeast around 5 mph, gusting to 24 mph.
Sunday night	Fair to partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 67°. Wind east-northeast around 6 mph, gusting to 19 mph.
Monday	Partly cloudy in the morning, becoming sunny in the afternoon. Hot. High 90°. UV index up to 8. Wind east around 5 mph, gusting to 24 mph.
Monday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 65°. Wind east around 5 mph, gusting to 19 mph.
Tuesday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 94°. UV index up to 7. Wind southeast around 5 mph, gusting to 22 mph.
Tuesday night	Mostly clear in the evening, becoming clear after midnight. Low 67°. Wind southeast around 7 mph, gusting to 16 mph, in the evening, becoming south after midnight.
Wednesday	Sunny in the morning, becoming partly to mostly cloudy in the afternoon. Extremely hot. High 99°. Heat index up to 103°. UV index up to 5. Wind west-southwest around 9 mph, gusting to 23 mph.
Wednesday night	Mostly clear in the evening, becoming clear after midnight. Low 68°. Wind east-northeast around 5 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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