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: Friday, 26-Jun-2026 04:00 pm

Tonight Thunder storm	Saturday Thunder storm	Saturday night Thunder storm	Sunday Fog a.m. Hot!	Sunday night Fog late	Monday Fog a.m. Hot!	Monday night Fog late	Tuesday Fog a.m. Hot!
.1 in.	<.1 in.	<.25 in.
Low: 70°	High: 85°	Low: 70°	High: 94°	Low: 73°	High: 96°	Low: 74°	High: 97°
			Heat: 103°		Heat: 108°		Heat: 109°
SW 1-18 mph	SW 3-20 mph	S 3-17 mph	SSW 8-25 mph	SSW 7-22 mph	SSW 8-26 mph	SSW 6-20 mph	SSW 6-24 mph
	UV: 7 High		UV: 10 Very High		UV: 9 Very High		UV: 9 Very High

Tonight	Partly cloudy in the evening, becoming cloudy after midnight. Light to moderate fog in the evening, then patchy light fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 70°. Wind southwest around 1 mph, gusting to 18 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Saturday	Cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. A chance of rain. Scattered thundershowers possible. High 85°. UV index up to 7. Wind southwest around 3 mph, gusting to 20 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Partly cloudy. Patchy light fog in the evening, then moderate fog after midnight. A chance of rain. Scattered thundershowers possible. Low 70°. Wind south around 3 mph, gusting to 17 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Sunday	Partly cloudy. Light to moderate fog in the morning. Hot. High 94°. Heat index up to 103°. UV index up to 10. Wind south-southwest around 8 mph, gusting to 25 mph.
Sunday night	Partly cloudy. Patchy light fog after midnight. Low 73°. Wind south-southwest around 7 mph, gusting to 22 mph.
Monday	Partly cloudy. Patchy light fog in the morning. Very hot. High 96°. Heat index up to 108°. UV index up to 9. Wind south-southwest around 8 mph, gusting to 26 mph.
Monday night	Mostly clear in the evening, becoming clear after midnight. Moderate fog after midnight. Low 74°. Wind south-southwest around 6 mph, gusting to 20 mph.
Tuesday	Sunny. Light to moderate fog in the morning. Very hot. High 97°. Heat index up to 109°. UV index up to 9. Wind south-southwest around 6 mph, gusting to 24 mph.
Tuesday night	Clear. Moderate fog after midnight. Low 74°. Wind south-southwest around 5 mph, gusting to 17 mph.
Wednesday	Sunny. Light to moderate fog in the morning. Very hot. High 97°. Heat index up to 108°. UV index up to 9. Wind south-southwest around 4 mph, gusting to 22 mph.
Wednesday night	Fair. Light to moderate fog after midnight. Low 74°. Wind south-southwest around 3 mph, gusting to 16 mph.
Thursday	Mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. Hot. High 94°. Heat index up to 104°. UV index up to 7. Wind south-southeast around 5 mph, gusting to 22 mph.
Thursday night	Clear in the evening, becoming partly cloudy after midnight. Patchy light fog in the evening, then moderate fog after midnight. Low 72°. Wind southeast around 6 mph, gusting to 20 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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