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: Friday, 21-Aug-2026 05:00 am

Today Mostly Sunny	Tonight Fog late	Saturday Fog a.m.	Saturday night Mostly Clear	Sunday Partly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Fog late
	<.1 in.
High: 88°	Low: 65°	High: 86°	Low: 64°	High: 85°	Low: 63°	High: 84°	Low: 63°

SSW 3-21 mph	WSW calm	NNW 5-22 mph	NNW 3-16 mph	NNW 3-22 mph	ENE 2-18 mph	ESE 4-22 mph	ESE 4-19 mph
UV: 8 Very High		UV: 7 High		UV: 7 High		UV: 6 High

Today	Mostly sunny. Hot. High 88°. UV index up to 8. Wind south-southwest around 3 mph, gusting to 21 mph.
Tonight	Fair to partly cloudy. Patchy light fog after midnight. A chance of rain. Low 65°. Wind west-southwest near calm. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday	Mostly sunny. Patchy light fog in the morning. High 86°. UV index up to 7. Wind north-northwest around 5 mph, gusting to 22 mph.
Saturday night	Fair in the evening, becoming mostly clear after midnight. Low 64°. Wind north-northwest around 3 mph, gusting to 16 mph.
Sunday	Partly cloudy. High 85°. UV index up to 7. Wind north-northwest around 3 mph, gusting to 22 mph.
Sunday night	Partly cloudy in the evening, becoming fair after midnight. Low 63°. Wind east-northeast around 2 mph, gusting to 18 mph.
Monday	Partly cloudy in the morning, becoming mostly cloudy in the afternoon. High 84°. UV index up to 6. Wind east-southeast around 4 mph, gusting to 22 mph.
Monday night	Fair in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 63°. Wind east-southeast around 4 mph, gusting to 19 mph.
Tuesday	Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. High 85°. UV index up to 7. Wind east-southeast around 5 mph, gusting to 21 mph.
Tuesday night	Mostly clear in the evening, becoming partly to mostly cloudy after midnight. Low 65°. Wind east-southeast around 3 mph, gusting to 19 mph.
Wednesday	Mostly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. A chance of rain. Scattered thundershowers possible. High 86°. UV index up to 7. Wind south-southeast around 3 mph, gusting to 16 mph, in the morning, becoming west in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Fair in the evening, becoming clear after midnight. Light to moderate fog after midnight. Low 66°. Wind west-northwest around 3 mph.
Thursday	Sunny. Light to moderate fog in the morning. Hot. High 87°. UV index up to 8. Wind northwest around 6 mph, gusting to 20 mph.
Thursday night	Mostly clear in the evening, becoming mostly cloudy after midnight. Low 66°. Wind north-northeast around 3 mph in the evening, becoming east after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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