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: Saturday, 22-Aug-2026 05:00 am

Today Mostly Sunny	Tonight Fog late	Sunday Chance rain	Sunday night Fog late	Monday Fog a.m.	Monday night Thunder storm	Tuesday Thunder storm	Tuesday night Fog late
		<.1 in.	<.1 in.		.5 in.	.1 in.
High: 87°	Low: 65°	High: 83°	Low: 66°	High: 85°	Low: 67°	High: 82°	Low: 67°

NNW 6-25 mph	NNW 3-19 mph	NNW 3-21 mph	SSE→ESE 2 mph	ESE 5-22 mph	ESE 6-20 mph	ESE 4-17 mph	ESE→WNW 2-16 mph
UV: 7 High		UV: 7 High		UV: 7 High		UV: 5 Medium

Today	Mostly sunny. Hot. High 87°. UV index up to 7. Wind north-northwest around 6 mph, gusting to 25 mph.
Tonight	Fair in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 65°. Wind north-northwest around 3 mph, gusting to 19 mph.
Sunday	Partly cloudy. Patchy light fog in the morning. A chance of rain. High 83°. UV index up to 7. Wind north-northwest around 3 mph, gusting to 21 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Partly cloudy in the evening, becoming clear after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain. Low 66°. Wind south-southeast around 2 mph in the evening, becoming east-southeast after midnight. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Monday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. High 85°. UV index up to 7. Wind east-southeast around 5 mph, gusting to 22 mph.
Monday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Moderate fog after midnight. Rain likely after midnight. Scattered thundershowers possible. Low 67°. Wind east-southeast around 6 mph, gusting to 20 mph. Chance of precipitation 60 percent. Precipitation mostly around half an inch.
Tuesday	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 82°. UV index up to 5. Wind east-southeast around 4 mph, gusting to 17 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Tuesday night	Fair. Light to moderate fog after midnight. Low 67°. Wind east-southeast around 2 mph, gusting to 16 mph, in the evening, becoming west-northwest after midnight.
Wednesday	Partly cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. High 85°. UV index up to 6. Wind southwest around 3 mph, gusting to 19 mph, in the morning, becoming west-northwest in the afternoon.
Wednesday night	Fair in the evening, becoming mostly clear after midnight. Light to moderate fog after midnight. Low 67°. Wind south around 2 mph in the evening, becoming west-northwest after midnight.
Thursday	Sunny. Light to moderate fog in the morning. High 85°. UV index up to 7. Wind northwest around 6 mph, gusting to 22 mph.
Thursday night	Clear. Patchy light fog after midnight. Low 64°. Wind north-northeast around 5 mph, gusting to 17 mph, in the evening, becoming near calm after midnight.
Friday	Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 83°. UV index up to 7. Wind east-northeast around 2 mph, gusting to 20 mph.
Friday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. Low 66°. Wind east-southeast around 4 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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