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: Tuesday, 25-Aug-2026 04:00 pm

Tonight Fog late	Wednesday Fog a.m.	Wednesday night Chance rain	Thursday Fog a.m.	Thursday night Fog late	Friday Fog a.m.	Friday night Fog late	Saturday Fog a.m.
<.1 in.	<.1 in.	.1 in.
Low: 70°	High: 89°	Low: 68°	High: 85°	Low: 63°	High: 84°	Low: 62°	High: 88°
	Heat: 94°
ESE→SSE 4-19 mph	SW→W 4-22 mph	NW 3-16 mph	NW 5-24 mph	NNE 3-19 mph	NNE 3-21 mph	E 3 mph	SSE 4-21 mph
	UV: 6 High		UV: 7 High		UV: 7 High		UV: 7 High

Tonight	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A chance of rain. Low 70°. Wind east-southeast around 4 mph, gusting to 19 mph, in the evening, becoming south-southeast after midnight. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday	Partly cloudy. Patchy light fog in the morning. A chance of rain. Hot. High 89°. Heat index up to 94°. UV index up to 6. Wind southwest around 4 mph, gusting to 22 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 to partly cloudy in the evening, becoming clear after midnight. Moderate fog in the evening, then light to moderate fog after midnight. A chance of rain. Low 68°. Wind northwest around 3 mph, gusting to 16 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Thursday	Sunny. Light to moderate fog in the morning. High 85°. UV index up to 7. Wind northwest around 5 mph, gusting to 24 mph.
Thursday night	Clear. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 19 mph.
Friday	Sunny. Patchy light fog in the morning. High 84°. UV index up to 7. Wind north-northeast around 3 mph, gusting to 21 mph.
Friday night	Fair to partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 62°. Wind east around 3 mph.
Saturday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 88°. UV index up to 7. Wind south-southeast around 4 mph, gusting to 21 mph.
Saturday night	Fair to partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 64°. Wind south-southeast around 4 mph, gusting to 15 mph.
Sunday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 92°. Heat index up to 96°. UV index up to 7. Wind south-southeast around 7 mph, gusting to 24 mph.
Sunday night	Fair in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 67°. Wind south around 7 mph, gusting to 18 mph.
Monday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Very hot. High 93°. Heat index up to 99°. UV index up to 6. Wind south-southwest around 8 mph, gusting to 21 mph.
Monday night	Clear. Patchy light fog after midnight. Low 68°. Wind south around 5 mph, gusting to 16 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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