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, 12-Sep-2026 04:00 pm

Tonight Partly Cloudy	Sunday Partly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Clear	Tuesday Mostly Sunny	Tuesday night Chance rain	Wednesday Fog a.m.
						.1 in.
Low: 68°	High: 88°	Low: 63°	High: 86°	Low: 63°	High: 96°	Low: 65°	High: 91°

NNW 3-23 mph	NNE 4-23 mph	NE 5-22 mph	ESE 8-26 mph	SSE 8-21 mph	SSW→WSW 6-23 mph	NNE 3 mph	NE→SSW 3-18 mph
	UV: 6 High		UV: 6 High		UV: 7 High		UV: 6 High

Tonight	Clear in the evening, becoming partly cloudy after midnight. Low 68°. Wind north-northwest around 3 mph, gusting to 23 mph.
Sunday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Hot. High 88°. UV index up to 6. Wind north-northeast around 4 mph, gusting to 23 mph.
Sunday night	Fair to partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 63°. Wind northeast around 5 mph, gusting to 22 mph.
Monday	Mostly cloudy in the morning, becoming partly cloudy in the afternoon. Hot. High 86°. UV index up to 6. Wind east-southeast around 8 mph, gusting to 26 mph.
Monday night	Clear. Low 63°. Wind south-southeast around 8 mph, gusting to 21 mph.
Tuesday	Partly to mostly sunny. Very hot. High 96°. UV index up to 7. Wind south-southwest around 6 mph, gusting to 23 mph, in the morning, becoming west-southwest in the afternoon.
Tuesday night	Partly cloudy. Light to moderate fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Precipitation showery or intermittent. Low 65°. Wind north-northeast around 3 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Wednesday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 91°. UV index up to 6. Wind northeast around 3 mph, gusting to 18 mph, in the morning, becoming south-southwest in the afternoon.
Wednesday night	Partly cloudy. Low 67°. Wind south-southwest around 3 mph.
Thursday	Partly to mostly sunny. Patchy light fog in the morning. A slight chance of rain. Precipitation showery or intermittent. Very hot. High 94°. Heat index up to 99°. UV index up to 7. Wind south-southwest around 5 mph, gusting to 21 mph, in the morning, becoming northwest in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Partly cloudy. Patchy light fog. A chance of rain in the evening, then a slight chance of rain after midnight. Low 69°. Wind northeast around 3 mph in the evening, becoming east-southeast after midnight. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Friday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Moderate fog in the morning. Unusually hot. High 89°. Heat index up to 94°. UV index up to 6. Wind east-northeast around 4 mph, gusting to 23 mph.
Friday night	Mostly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Precipitation showery or intermittent. Low 69°. Wind east-northeast around 3 mph in the evening, becoming south-southeast 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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