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 04:00 pm

Tonight Clear	Monday Sunny Hot!	Monday night Clear	Tuesday Sunny Hot!	Tuesday night Fog late	Wednesday Fog a.m. Hot!	Wednesday night Fog late	Thursday Fog a.m. Hot!

Low: 70°	High: 96°	Low: 70°	High: 97°	Low: 70°	High: 98°	Low: 71°	High: 97°
	Heat: 102°		Heat: 103°		Heat: 105°		Heat: 106°
S 7-23 mph	SSW 7-23 mph	S 5 mph	SW 6-21 mph	S 5 mph	SW 6-22 mph	S 5 mph	SW 5-19 mph
	UV: 8 Very High		UV: 8 Very High		UV: 8 Very High		UV: 8 Very High

Tonight	Clear in the evening, becoming fair after midnight. Low 70°. Wind south around 7 mph, gusting to 23 mph.
Monday	Sunny. Very hot. High 96°. Heat index up to 102°. UV index up to 8. Wind south-southwest around 7 mph, gusting to 23 mph.
Monday night	Clear. Low 70°. Wind south around 5 mph.
Tuesday	Sunny. Very hot. High 97°. Heat index up to 103°. UV index up to 8. Wind southwest around 6 mph, gusting to 21 mph.
Tuesday night	Clear. Patchy light fog after midnight. Low 70°. Wind south around 5 mph.
Wednesday	Sunny. Patchy light fog in the morning. Very hot. High 98°. Heat index up to 105°. UV index up to 8. Wind southwest around 6 mph, gusting to 22 mph.
Wednesday night	Clear. Patchy light fog after midnight. Low 71°. Wind south around 5 mph.
Thursday	Sunny. Patchy light fog in the morning. Very hot. High 97°. Heat index up to 106°. UV index up to 8. Wind southwest around 5 mph, gusting to 19 mph.
Thursday night	Clear. Patchy light fog after midnight. Low 71°. Wind south around 4 mph.
Friday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 99°. Heat index up to 108°. UV index up to 8. Wind southwest around 5 mph, gusting to 21 mph, in the morning, becoming north in the afternoon.
Friday night	Mostly clear in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 72°. Wind south-southeast around 3 mph.
Saturday	Partly cloudy in the morning, becoming partly to 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. Very hot. High 93°. Heat index up to 101°. UV index up to 6. Wind southwest around 4 mph, gusting to 19 mph, in the morning, becoming east in the afternoon. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Saturday night	Mostly clear in the evening, becoming fair after midnight. Patchy light fog. Low 71°. Wind south-southwest around 2 mph in the evening, becoming southeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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