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, 23-Aug-2026 05:00 am

Today Chance rain	Tonight Fog late	Monday Fog a.m.	Monday night Fog	Tuesday Fog a.m.	Tuesday night Partly Cloudy	Wednesday Partly Cloudy	Wednesday night Chance rain
<.1 in.		<.1 in.	<.1 in.				<.25 in.
High: 81°	Low: 60°	High: 82°	Low: 63°	High: 85°	Low: 63°	High: 87°	Low: 66°

WNW 5-23 mph	NNE→E 2-16 mph	ESE 2-20 mph	E 4-16 mph	ESE 5-21 mph	ESE 4-17 mph	S→WSW 4-20 mph	NNW 3 mph
UV: 7 High		UV: 7 High		UV: 6 High		UV: 6 High

Today	Partly cloudy. A chance of rain. High 81°. UV index up to 7. Wind west-northwest around 5 mph, gusting to 23 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Tonight	Fair. Patchy light fog after midnight. Relatively cool. Low 60°. Wind north-northeast around 2 mph, gusting to 16 mph, in the evening, becoming east after midnight.
Monday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. High 82°. UV index up to 7. Wind east-southeast around 2 mph, gusting to 20 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Patchy light fog. A chance of rain. Low 63°. Wind east around 4 mph, gusting to 16 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tuesday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Light to moderate fog in the morning. High 85°. UV index up to 6. Wind east-southeast around 5 mph, gusting to 21 mph.
Tuesday night	Fair to partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 63°. Wind east-southeast around 4 mph, gusting to 17 mph.
Wednesday	Partly cloudy. Hot. High 87°. UV index up to 6. Wind south around 4 mph, gusting to 20 mph, in the morning, becoming west-southwest in the afternoon.
Wednesday night	Partly cloudy in the evening, becoming clear after midnight. Light to moderate fog in the evening, then moderate fog after midnight. A chance of rain. Low 66°. Wind north-northwest around 3 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Thursday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. High 86°. UV index up to 7. Wind north-northwest around 4 mph, gusting to 21 mph.
Thursday night	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 63°. Wind northeast around 2 mph.
Friday	Sunny. Patchy light fog in the morning. High 85°. UV index up to 7. Wind north around 2 mph, gusting to 18 mph.
Friday night	Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. Low 66°. Wind east-southeast around 3 mph.
Saturday	Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. High 86°. UV index up to 6. Wind southeast around 5 mph, gusting to 18 mph, in the morning, becoming 11 mph, gusting to 25 mph, in the afternoon.
Saturday night	Cloudy. A chance of rain in the evening, then a slight chance of rain after midnight. Low 69°. Wind south-southeast around 8 mph, gusting to 22 mph, in the evening, becoming 4 mph after midnight. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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