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, 28-Jul-2026 04:00 pm

Tonight Thunder storm	Wednesday Fog a.m.	Wednesday night Fog late	Thursday Chance rain	Thursday night Fog late	Friday Rain likely	Friday night Rain likely	Saturday Chance rain
.1 in.			<.1 in.	<.1 in.	.1 in.	<.25 in.	<.1 in.
Low: 73°	High: 90°	Low: 68°	High: 88°	Low: 69°	High: 87°	Low: 73°	High: 80°
	Heat: 96°		Heat: 93°
NE 5-15 mph	E 5-24 mph	E 4-21 mph	E 5-22 mph	E→SE 6-20 mph	SE 8-25 mph	S→W 8-23 mph	WNW 13-30 mph
	UV: 9 Very High		UV: 8 Very High		UV: 9 Very High		UV: 6 High

Tonight	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Patchy light fog in the evening, then moderate fog after midnight. Rain likely. Scattered thunderstorms likely. Low 73°. Wind northeast around 5 mph, gusting to 15 mph. Chance of precipitation 60 percent. Precipitation mostly around a tenth of an inch.
Wednesday	Mostly sunny. Moderate fog in the morning. Hot. High 90°. Heat index up to 96°. UV index up to 9. Wind east around 5 mph, gusting to 24 mph.
Wednesday night	Fair. Patchy light fog after midnight. Low 68°. Wind east around 4 mph, gusting to 21 mph.
Thursday	Partly to mostly sunny. Patchy light fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. High 88°. Heat index up to 93°. UV index up to 8. Wind east around 5 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A chance of rain after midnight. Low 69°. Wind east around 6 mph, gusting to 20 mph, in the evening, becoming southeast after midnight. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Friday	Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Rain likely. Precipitation showery or intermittent. High 87°. UV index up to 9. Wind southeast around 8 mph, gusting to 25 mph. Chance of precipitation 60 percent. Precipitation mostly around a tenth of an inch.
Friday night	Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Light to moderate fog in the evening, then patchy light fog after midnight. Rain likely in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Low 73°. Wind south around 8 mph, gusting to 23 mph, in the evening, becoming west after midnight. Chance of precipitation 70 percent. Precipitation mostly less than a quarter of an inch.
Saturday	Cloudy in the morning, becoming mostly cloudy in the afternoon. A chance of rain. Breezy. High 80°. UV index up to 6. Wind west-northwest around 13 mph, gusting to 30 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Fair to partly cloudy in the evening, becoming fair after midnight. Patchy light fog after midnight. A chance of rain. Low 68°. Wind northwest around 11 mph, gusting to 28 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A chance of rain. Breezy. High 82°. UV index up to 8. Wind north-northwest around 11 mph, gusting to 28 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Fair to partly cloudy. Light to moderate fog after midnight. A chance of rain. Relatively cool. Low 66°. Wind north around 7 mph, gusting to 25 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Monday	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 85°. UV index up to 7. Wind north-northeast around 7 mph, gusting to 24 mph. Chance of precipitation 50 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Relatively cool. Low 66°. Wind east-northeast around 6 mph, gusting to 19 mph, in the evening, becoming 2 mph after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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