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: Sunday, 30-Aug-2026 05:00 am

Today Mostly Sunny	Tonight Fair	Monday Partly Cloudy Hot!	Monday night Clear	Tuesday Sunny Hot!	Tuesday night Clear	Wednesday Sunny Hot!	Wednesday night Clear

High: 98°	Low: 70°	High: 98°	Low: 71°	High: 99°	Low: 72°	High: 100°	Low: 72°
		Heat: 102°		Heat: 105°		Heat: 107°
SSW 7-26 mph	SSE 6-20 mph	SSW 7-23 mph	SSW 5-16 mph	SSW 6-23 mph	S 5 mph	SW 5-23 mph	S 4 mph
UV: 7 High		UV: 7 High		UV: 8 Very High		UV: 8 Very High

Today	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 98°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 26 mph.
Tonight	Fair. Low 70°. Wind south-southeast around 6 mph, gusting to 20 mph.
Monday	Partly cloudy. Very hot. High 98°. Heat index up to 102°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 23 mph.
Monday night	Clear. Low 71°. Wind south-southwest around 5 mph, gusting to 16 mph.
Tuesday	Sunny. Extremely hot. High 99°. Heat index up to 105°. UV index up to 8. Wind south-southwest around 6 mph, gusting to 23 mph.
Tuesday night	Clear. Low 72°. Wind south around 5 mph.
Wednesday	Sunny. Extremely hot. High 100°. Heat index up to 107°. UV index up to 8. Wind southwest around 5 mph, gusting to 23 mph.
Wednesday night	Clear. Low 72°. Wind south around 4 mph.
Thursday	Sunny in the morning, becoming mostly sunny in the afternoon. Extremely hot. High 100°. Heat index up to 109°. UV index up to 8. Wind south-southwest around 5 mph, gusting to 22 mph.
Thursday night	Mostly clear in the evening, becoming clear after midnight. Low 72°. Wind south-southwest around 4 mph.
Friday	Sunny. Extremely hot. High 99°. Heat index up to 109°. UV index up to 8. Wind west-southwest around 4 mph, gusting to 21 mph.
Friday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Warm. Low 74°. Wind east-southeast around 3 mph in the evening, becoming southwest after midnight.
Saturday	Partly to mostly cloudy in the morning, becoming mostly sunny in the afternoon. Very hot. High 98°. Heat index up to 107°. UV index up to 7. Wind west-northwest around 2 mph, gusting to 19 mph, in the morning, becoming southeast in the afternoon.
Saturday night	Mostly cloudy in the evening, becoming partly to mostly cloudy after midnight. Moderate fog in the evening, then light to moderate fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 73°. Wind northeast around 5 mph in the evening, becoming east-southeast after midnight. Chance of precipitation 50 percent. Precipitation mostly around a quarter of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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