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, 26-Aug-2026 04:00 pm

Tonight Fog late	Thursday Fog a.m.	Thursday night Fog late	Friday Fog a.m.	Friday night Fog late	Saturday Fog a.m.	Saturday night Fog late	Sunday Fog a.m.

Low: 67°	High: 86°	Low: 63°	High: 86°	Low: 61°	High: 89°	Low: 66°	High: 94°
							Heat: 98°
NNW 4-23 mph	NW 5-23 mph	NNE 3-18 mph	NNE 3-21 mph	E 3-16 mph	SSE 5-22 mph	S 6-17 mph	S 8-24 mph
	UV: 7 High		UV: 7 High		UV: 7 High		UV: 8 Very High

Tonight	Fair in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 67°. Wind north-northwest around 4 mph, gusting to 23 mph.
Thursday	Sunny. Patchy light fog in the morning. Hot. High 86°. UV index up to 7. Wind northwest around 5 mph, gusting to 23 mph.
Thursday night	Clear. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 18 mph.
Friday	Sunny. Patchy light fog in the morning. Hot. High 86°. UV index up to 7. Wind north-northeast around 3 mph, gusting to 21 mph.
Friday night	Fair in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 61°. Wind east around 3 mph, gusting to 16 mph.
Saturday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 89°. UV index up to 7. Wind south-southeast around 5 mph, gusting to 22 mph.
Saturday night	Fair to partly cloudy. Patchy light fog after midnight. Low 66°. Wind south around 6 mph, gusting to 17 mph.
Sunday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 94°. Heat index up to 98°. UV index up to 8. Wind south around 8 mph, gusting to 24 mph.
Sunday night	Fair to partly cloudy in the evening, becoming fair after midnight. Low 69°. Wind south-southeast around 7 mph, gusting to 17 mph.
Monday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 97°. Heat index up to 103°. UV index up to 8. Wind south-southwest around 8 mph, gusting to 24 mph.
Monday night	Clear. Low 70°. Wind south-southwest around 7 mph, gusting to 16 mph.
Tuesday	Sunny. Very hot. High 99°. Heat index up to 106°. UV index up to 7. Wind south-southwest around 8 mph, gusting to 23 mph.
Tuesday night	Mostly clear in the evening, becoming clear after midnight. Low 71°. Wind south-southwest around 6 mph, gusting to 16 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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