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, 09-Jul-2026 04:00 pm

Tonight Thunder storm	Friday Thunder storm	Friday night Thunder storm	Saturday Thunder storm	Saturday night Fog late	Sunday Fog a.m.	Sunday night Fog late	Monday Fog a.m.
<.25 in.	.1 in.	.25 in.	<.25 in.
Low: 70°	High: 88°	Low: 72°	High: 85°	Low: 70°	High: 89°	Low: 68°	High: 89°
	Heat: 95°		Heat: 92°		Heat: 95°		Heat: 95°
S 4 mph	W→S 3-20 mph	NE→NNW 2-16 mph	NE 3-18→6-24 mph	NE 5-20 mph	NE 6-24 mph	NE 4-23 mph	ENE 5-24 mph
	UV: 7 High		UV: 8 Very High		UV: 9 Very High		UV: 9 Very High

Tonight	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. Rain likely. Scattered thunderstorms likely. Low 70°. Wind south around 4 mph. Chance of precipitation 70 percent. Precipitation mostly less than a quarter of an inch.
Friday	Mostly cloudy. Patchy light fog in the morning. Rain likely. Scattered thunderstorms likely. High 88°. Heat index up to 95°. UV index up to 7. Wind west around 3 mph, gusting to 20 mph, in the morning, becoming south in the afternoon. Chance of precipitation 60 percent. Precipitation mostly around a tenth of an inch.
Friday night	Mostly cloudy. Light to moderate fog. Rain likely in the evening, then a chance of rain after midnight. Scattered thunderstorms likely. Low 72°. Wind northeast around 2 mph, gusting to 16 mph, in the evening, becoming north-northwest after midnight. Chance of precipitation 80 percent. Precipitation mostly around a quarter of an inch.
Saturday	Partly to mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Light to moderate fog in the morning. Rain likely. Scattered thunderstorms likely. High 85°. Heat index up to 92°. UV index up to 8. Wind northeast around 3 mph, gusting to 18 mph, in the morning, becoming 6 mph, gusting to 24 mph, in the afternoon. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch.
Saturday night	Clear. Patchy light fog in the evening, then light to moderate fog after midnight. Low 70°. Wind northeast around 5 mph, gusting to 20 mph.
Sunday	Sunny. Light to moderate fog in the morning. High 89°. Heat index up to 95°. UV index up to 9. Wind northeast around 6 mph, gusting to 24 mph.
Sunday night	Clear. Patchy light fog after midnight. Low 68°. Wind northeast around 4 mph, gusting to 23 mph.
Monday	Sunny. Patchy light fog in the morning. High 89°. Heat index up to 95°. UV index up to 9. Wind east-northeast around 5 mph, gusting to 24 mph.
Monday night	Clear. Patchy light fog after midnight. Low 68°. Wind east-northeast around 3 mph, gusting to 20 mph.
Tuesday	Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Hot. High 91°. Heat index up to 97°. UV index up to 8. Wind northeast around 4 mph, gusting to 22 mph.
Tuesday night	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 68°. Wind east-northeast around 3 mph, gusting to 17 mph, in the evening, becoming south after midnight.
Wednesday	Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. Hot. High 91°. Heat index up to 97°. UV index up to 9. Wind north around 3 mph, gusting to 22 mph.
Wednesday night	Clear. Patchy light fog after midnight. Low 68°. Wind east-northeast around 1 mph, gusting to 16 mph, in the evening, becoming south-southwest after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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