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: Tuesday, 21-Jul-2026 05:00 am

Today Chance rain Hot!	Tonight Fog late	Wednesday Chance rain	Wednesday night Fog late	Thursday Fog a.m.	Thursday night Partly Cloudy	Friday Rain likely	Friday night Fog late
.1 in.	<.1 in.	.1 in.	<.1 in.			.35 in.	<.1 in.
High: 92°	Low: 70°	High: 83°	Low: 64°	High: 83°	Low: 63°	High: 78°	Low: 67°
Heat: 102°
NW 9-26 mph	N 7-23 mph	N 6-25 mph	NE 5-21 mph	ENE 5-24 mph	ENE 5-22 mph	ESE 4-22 mph	ESE 4-18 mph
UV: 8 Very High		UV: 7 High		UV: 8 Very High		UV: 6 High

Today	Partly cloudy. A chance of rain in the morning, then a slight chance of rain in the afternoon. Hot. High 92°. Heat index up to 102°. UV index up to 8. Wind northwest around 9 mph, gusting to 26 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Tonight	Fair to partly cloudy in the evening, becoming fair after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain. Low 70°. Wind north around 7 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday	Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Light to moderate fog in the morning. A chance of rain. High 83°. UV index up to 7. Wind north around 6 mph, gusting to 25 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Wednesday night	Partly to mostly cloudy in the evening, becoming fair after midnight. Patchy light fog after midnight. A chance of rain. Relatively cool. Low 64°. Wind northeast around 5 mph, gusting to 21 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 83°. UV index up to 8. Wind east-northeast around 5 mph, gusting to 24 mph.
Thursday night	Partly cloudy. Relatively cool. Low 63°. Wind east-northeast around 5 mph, gusting to 22 mph.
Friday	Mostly cloudy to cloudy in the morning, becoming cloudy in the afternoon. Rain likely. Relatively cool. High 78°. UV index up to 6. Wind east-southeast around 4 mph, gusting to 22 mph. Chance of precipitation 60 percent. Precipitation mostly between a quarter and half an inch.
Friday night	Mostly cloudy to cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain. Relatively cool. Low 67°. Wind east-southeast around 4 mph, gusting to 18 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday	Partly cloudy in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 91°. Heat index up to 95°. UV index up to 9. Wind southeast around 4 mph, gusting to 23 mph.
Saturday night	Mostly clear in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. Low 70°. Wind east-southeast around 3 mph, gusting to 18 mph, in the evening, becoming south-southeast after midnight.
Sunday	Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Hot. High 94°. Heat index up to 101°. UV index up to 8. Wind south-southeast around 4 mph, gusting to 20 mph.
Sunday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 73°. Wind south-southwest around 4 mph in the evening, becoming 8 mph after midnight.
Monday	Partly cloudy in the morning, becoming sunny in the afternoon. Breezy and very hot. High 100°. Heat index up to 109°. UV index up to 9. Wind west-southwest around 13 mph, gusting to 29 mph.
Monday night	Clear. Patchy light fog after midnight. Low 72°. Wind west-northwest around 6 mph, gusting to 22 mph, in the evening, becoming north-northwest after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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