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: Sunday, 12-Jul-2026 04:00 pm

Tonight Fog late	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Fog late	Wednesday Fog a.m.	Wednesday night Fog late	Thursday Thunder storm Hot!
							<.1 in.
Low: 69°	High: 89°	Low: 67°	High: 92°	Low: 69°	High: 93°	Low: 70°	High: 93°
	Heat: 93°		Heat: 96°		Heat: 99°		Heat: 100°
NE 4-24 mph	NE 5-25 mph	NE 3-21 mph	NE 5-24 mph	ENE 2-20 mph	ENE 3-22 mph	ESE→S 2-17 mph	S 3-22 mph
	UV: 9 Very High		UV: 9 Very High		UV: 9 Very High		UV: 9 Very High

Tonight	Fair. Light to moderate fog after midnight. Low 69°. Wind northeast around 4 mph, gusting to 24 mph.
Monday	Mostly sunny. Patchy light fog in the morning. High 89°. Heat index up to 93°. UV index up to 9. Wind northeast around 5 mph, gusting to 25 mph.
Monday night	Fair. Patchy light fog after midnight. Relatively cool. Low 67°. Wind northeast around 3 mph, gusting to 21 mph.
Tuesday	Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. Hot. High 92°. Heat index up to 96°. UV index up to 9. Wind northeast around 5 mph, gusting to 24 mph.
Tuesday night	Clear. Patchy light fog after midnight. Low 69°. Wind east-northeast around 2 mph, gusting to 20 mph.
Wednesday	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 99°. UV index up to 9. Wind east-northeast around 3 mph, gusting to 22 mph.
Wednesday night	Mostly clear in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 70°. Wind east-southeast around 2 mph, gusting to 17 mph, in the evening, becoming south after midnight.
Thursday	Partly cloudy. Patchy light fog in the morning. A chance of rain. Scattered thundershowers possible. Hot. High 93°. Heat index up to 100°. UV index up to 9. Wind south around 3 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Partly cloudy. Light to moderate fog after midnight. Low 73°. Wind south-southwest around 3 mph, gusting to 17 mph.
Friday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Light to moderate fog in the morning. A chance of rain. Scattered thundershowers possible. Hot. High 95°. Heat index up to 104°. UV index up to 9. Wind southwest around 5 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Friday night	Partly to mostly cloudy in the evening, becoming fair to partly cloudy after midnight. Moderate fog after midnight. A chance of rain. Scattered thunderstorms likely. Low 74°. Wind southwest around 6 mph, gusting to 19 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday	Sunny. Moderate fog in the morning. Hot. High 96°. Heat index up to 106°. UV index up to 9. Wind west-southwest around 5 mph, gusting to 23 mph.
Saturday night	Clear. Patchy light fog after midnight. Low 71°. Wind west around 4 mph, gusting to 19 mph, in the evening, becoming south-southwest after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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