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: Saturday, 11-Jul-2026 04:00 pm

Tonight Chance rain	Sunday Chance rain	Sunday night Fog late	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Fog late	Wednesday Fog a.m.
.1 in.	<.1 in.
Low: 72°	High: 86°	Low: 69°	High: 89°	Low: 69°	High: 91°	Low: 69°	High: 92°
			Heat: 95°		Heat: 97°		Heat: 98°
N 5-22 mph	N 7-25 mph	N 5-22 mph	NNE 5-25→8-26 mph	NNE 3-22 mph	NNE 5-25 mph	ENE 2-20 mph	NE 3-22 mph
	UV: 8 Very High		UV: 9 Very High		UV: 9 Very High		UV: 9 Very High

Tonight	Fair to partly cloudy. Light to moderate fog in the evening, then moderate fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Low 72°. Wind north around 5 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Sunday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Moderate fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. High 86°. UV index up to 8. Wind north around 7 mph, gusting to 25 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Fair. Patchy light fog in the evening, then light to moderate fog after midnight. Low 69°. Wind north around 5 mph, gusting to 22 mph.
Monday	Mostly sunny in the morning, becoming sunny in the afternoon. Light to moderate fog in the morning. High 89°. Heat index up to 95°. UV index up to 9. Wind north-northeast around 5 mph, gusting to 25 mph, in the morning, becoming 8 mph, gusting to 26 mph, in the afternoon.
Monday night	Clear. Patchy light fog after midnight. Low 69°. Wind north-northeast around 3 mph, gusting to 22 mph.
Tuesday	Sunny. Patchy light fog in the morning. Hot. High 91°. Heat index up to 97°. UV index up to 9. Wind north-northeast around 5 mph, gusting to 25 mph.
Tuesday night	Clear. Patchy light fog after midnight. Low 69°. Wind east-northeast around 2 mph, gusting to 20 mph.
Wednesday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 92°. Heat index up to 98°. UV index up to 9. Wind northeast around 3 mph, gusting to 22 mph.
Wednesday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 70°. Wind east around 2 mph, gusting to 16 mph, in the evening, becoming southwest after midnight.
Thursday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 93°. Heat index up to 100°. UV index up to 9. Wind west around 2 mph, gusting to 21 mph, in the morning, becoming east-southeast in the afternoon.
Thursday night	Mostly clear. Light to moderate fog after midnight. Low 71°. Wind south-southwest around 2 mph.
Friday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Scattered thundershowers possible. High 89°. Heat index up to 97°. UV index up to 8. Wind west-southwest around 6 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Friday night	Mostly clear. Patchy light fog in the evening, then light to moderate fog after midnight. Low 73°. Wind west-southwest around 4 mph, gusting to 17 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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