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, 27-Aug-2026 04:00 pm

Tonight Fog late	Friday Fog a.m.	Friday night Fog late	Saturday Fog a.m.	Saturday night Fog late	Sunday Fog a.m.	Sunday night Partly Cloudy	Monday Mostly Sunny

Low: 63°	High: 84°	Low: 61°	High: 88°	Low: 63°	High: 91°	Low: 67°	High: 98°

NNE 3-21 mph	NNW→NNE 3-21 mph	E 2 mph	SE→S 4-22 mph	S 5-17 mph	S 7-22 mph	S 6-16 mph	S 7-24 mph
	UV: 7 High		UV: 7 High		UV: 7 High		UV: 7 High

Tonight	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 21 mph.
Friday	Sunny. Patchy light fog in the morning. High 84°. UV index up to 7. Wind north-northwest around 3 mph, gusting to 21 mph, in the morning, becoming north-northeast in the afternoon.
Friday night	Clear in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 61°. Wind east around 2 mph.
Saturday	Partly cloudy. Patchy light fog in the morning. Hot. High 88°. UV index up to 7. Wind southeast around 4 mph, gusting to 22 mph, in the morning, becoming south in the afternoon.
Saturday night	Mostly clear in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 63°. Wind south around 5 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. Hot. High 91°. UV index up to 7. Wind south around 7 mph, gusting to 22 mph.
Sunday night	Partly cloudy in the evening, becoming fair after midnight. Low 67°. Wind south around 6 mph, gusting to 16 mph.
Monday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 98°. UV index up to 7. Wind south around 7 mph, gusting to 24 mph.
Monday night	Clear. Low 68°. Wind south around 6 mph, gusting to 16 mph.
Tuesday	Sunny. Very hot. High 98°. Heat index up to 102°. UV index up to 8. Wind southwest around 6 mph, gusting to 22 mph.
Tuesday night	Clear. Low 69°. Wind south around 5 mph.
Wednesday	Sunny. Very hot. High 98°. Heat index up to 105°. UV index up to 7. Wind southwest around 8 mph, gusting to 21 mph.
Wednesday night	Partly cloudy in the evening, becoming clear after midnight. Low 71°. Wind southwest around 6 mph, gusting to 15 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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