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, 01-Aug-2026 04:00 pm

Tonight Rain likely	Sunday Chance rain	Sunday night Chance rain	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Partly Cloudy	Wednesday Mostly Sunny
<.25 in.	<.1 in.	<.1 in.	<.1 in.
Low: 65°	High: 79°	Low: 63°	High: 83°	Low: 63°	High: 88°	Low: 66°	High: 92°
							Heat: 96°
NNW 11-25 mph	NNW 10-25 mph	NNE 4-20 mph	NNE 3-21 mph	ENE→ESE 3-16 mph	ESE 3-21 mph	SE 4-17 mph	SSE 4-23 mph
	UV: 7 High		UV: 8 Very High		UV: 9 Very High		UV: 9 Very High

Tonight	Cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog after midnight. Rain likely. Precipitation showery or intermittent. Relatively cool. Low 65°. Wind north-northwest around 11 mph, gusting to 25 mph. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch.
Sunday	Partly cloudy. Light to moderate fog in the morning. A chance of rain. High 79°. UV index up to 7. Wind north-northwest around 10 mph, gusting to 25 mph. Chance of precipitation 50 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Fair to partly cloudy. Light to moderate fog in the evening, then moderate fog after midnight. A chance of rain. Relatively cool. Low 63°. Wind north-northeast around 4 mph, gusting to 20 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Monday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Moderate fog in the morning. A chance of rain. High 83°. UV index up to 8. Wind north-northeast around 3 mph, gusting to 21 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Clear. Patchy light fog after midnight. Relatively cool. Low 63°. Wind east-northeast around 3 mph, gusting to 16 mph, in the evening, becoming east-southeast after midnight.
Tuesday	Sunny. Patchy light fog in the morning. High 88°. UV index up to 9. Wind east-southeast around 3 mph, gusting to 21 mph.
Tuesday night	Clear in the evening, becoming fair to partly cloudy after midnight. Relatively cool. Low 66°. Wind southeast around 4 mph, gusting to 17 mph.
Wednesday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Hot. High 92°. Heat index up to 96°. UV index up to 9. Wind south-southeast around 4 mph, gusting to 23 mph.
Wednesday night	Partly cloudy. A slight chance of rain. Low 69°. Wind southeast around 6 mph, gusting to 17 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Mostly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Rain likely. Scattered thunderstorms likely. High 87°. Heat index up to 94°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 20 mph. Chance of precipitation 70 percent. Precipitation mostly around a quarter of an inch.
Thursday night	Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog after midnight. Low 70°. Wind north around 5 mph, gusting to 20 mph.
Friday	Partly cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Scattered thundershowers possible. High 90°. Heat index up to 95°. UV index up to 6. Wind south around 7 mph, gusting to 22 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Friday night	Mostly cloudy to cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog. A chance of rain. Scattered thunderstorms likely. Low 72°. Wind south-southwest around 7 mph, gusting to 15 mph, in the evening, becoming 2 mph after midnight. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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