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, 02-Aug-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 Chance rain	Thursday Thunder storm
<.1 in.	<.1 in.					.1 in.	.1 in.
Low: 67°	High: 84°	Low: 66°	High: 88°	Low: 66°	High: 92°	Low: 70°	High: 88°
			Heat: 92°		Heat: 96°		Heat: 94°
NE 3-23 mph	NE 3-21 mph	ESE 3-15 mph	SE 4-22 mph	SE 5-18 mph	S 5-23 mph	E→SSW 5-17 mph	SW 4-21 mph
	UV: 8 Very High		UV: 8 Very High		UV: 9 Very High		UV: 6 High

Tonight	Fair to partly cloudy. Patchy light fog in the evening, then moderate fog after midnight. A chance of rain. Low 67°. Wind northeast around 3 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Monday	Partly to mostly sunny. Light to moderate fog in the morning. A chance of rain. High 84°. UV index up to 8. Wind northeast around 3 mph, gusting to 21 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Fair. Light to moderate fog after midnight. Relatively cool. Low 66°. Wind east-southeast around 3 mph, gusting to 15 mph.
Tuesday	Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. High 88°. Heat index up to 92°. UV index up to 8. Wind southeast around 4 mph, gusting to 22 mph.
Tuesday night	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Relatively cool. Low 66°. Wind southeast around 5 mph, gusting to 18 mph.
Wednesday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 92°. Heat index up to 96°. UV index up to 9. Wind south around 5 mph, gusting to 23 mph.
Wednesday night	Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Patchy light fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Low 70°. Wind east around 5 mph, gusting to 17 mph, in the evening, becoming south-southwest after midnight. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Thursday	Mostly cloudy. Light to moderate fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Scattered thundershowers possible. High 88°. Heat index up to 94°. UV index up to 6. Wind southwest around 4 mph, gusting to 21 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Thursday night	Partly to mostly cloudy in the evening, becoming fair to partly cloudy after midnight. Light to moderate fog. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 72°. Wind east-northeast around 2 mph, gusting to 16 mph, in the evening, becoming south-southeast after midnight. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch.
Friday	Mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. A chance of rain. High 88°. Heat index up to 94°. UV index up to 8. Wind west around 3 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Friday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Light to moderate fog after midnight. Low 72°. Wind east-southeast around 3 mph, gusting to 18 mph.
Saturday	Partly cloudy in the morning, becoming mostly cloudy in the afternoon. Light to moderate fog in the morning. A slight chance of rain in the afternoon. Scattered thunderstorms likely. Hot. High 92°. Heat index up to 99°. UV index up to 6. Wind southwest around 5 mph, gusting to 18 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Partly cloudy in the evening, becoming clear after midnight. Patchy light fog in the evening, then moderate fog after midnight. Low 72°. Wind southeast around 8 mph, gusting to 16 mph, in the evening, becoming south-southwest around 5 mph after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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