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 04:00 pm

Tonight Fair	Sunday Chance rain	Sunday night Fog late	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Partly Cloudy	Wednesday Thunder storm
	<.1 in.		<.1 in.		<.1 in.		<.1 in.
Low: 65°	High: 82°	Low: 64°	High: 83°	Low: 67°	High: 86°	Low: 68°	High: 85°

NNW 3-20 mph	NNW 4-22 mph	NE→E 3 mph	SE 4-21 mph	E 6-20 mph	ESE 5-23 mph	ENE→SE 3-19 mph	SSW→W 3-18 mph
	UV: 7 High		UV: 6 High		UV: 6 High		UV: 5 Medium

Tonight	Fair. Low 65°. Wind north-northwest around 3 mph, gusting to 20 mph.
Sunday	Partly cloudy. Patchy light fog in the morning. A chance of rain. High 82°. UV index up to 7. Wind north-northwest around 4 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Fair. Patchy light fog after midnight. Low 64°. Wind northeast around 3 mph in the evening, becoming east after midnight.
Monday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. High 83°. UV index up to 6. Wind southeast around 4 mph, gusting to 21 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Partly cloudy. Patchy light fog after midnight. Low 67°. Wind east around 6 mph, gusting to 20 mph.
Tuesday	Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. Precipitation showery or intermittent. High 86°. UV index up to 6. Wind east-southeast around 5 mph, gusting to 23 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. Low 68°. Wind east-northeast around 3 mph, gusting to 19 mph, in the evening, becoming southeast after midnight.
Wednesday	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. A chance of rain. Scattered thundershowers possible. High 85°. UV index up to 5. Wind south-southwest around 3 mph, gusting to 18 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 mostly clear after midnight. Patchy light fog after midnight. Low 66°. Wind southwest around 3 mph in the evening, becoming west-northwest after midnight.
Thursday	Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. High 86°. UV index up to 7. Wind northwest around 5 mph, gusting to 22 mph.
Thursday night	Clear. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 17 mph.
Friday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 88°. UV index up to 8. Wind south around 2 mph, gusting to 18 mph, in the morning, becoming east in the afternoon.
Friday night	Clear in the evening, becoming partly cloudy after midnight. Low 62°. Wind east-southeast around 6 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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