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, 11-Jul-2026 05:00 am

Today Thunder storm	Tonight Thunder storm	Sunday Fog a.m.	Sunday night Clear	Monday Sunny	Monday night Clear	Tuesday Mostly Sunny	Tuesday night Partly Cloudy
.25 in.	<.1 in.
High: 81°	Low: 67°	High: 84°	Low: 66°	High: 88°	Low: 66°	High: 89°	Low: 69°
				Heat: 91°		Heat: 93°
NW→N 4-21→8-25 mph	NNE 7-22 mph	NNE 9-27 mph	NNE 5-23 mph	N 6-26→9-27 mph	NNE 4-23 mph	NE 4-24→8-25 mph	NE 3-19 mph
UV: 8 Very High		UV: 9 Very High		UV: 9 Very High		UV: 8 Very High

Today	Mostly cloudy in the morning, becoming partly cloudy in the afternoon. Rain likely. Thunderstorms very likely, some severe. High 81°. UV index up to 8. Wind northwest around 4 mph, gusting to 21 mph, in the morning, becoming north around 8 mph, gusting to 25 mph, in the afternoon. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch.
Tonight	Fair to partly cloudy. Moderate fog. A chance of rain. Scattered thundershowers possible. Relatively cool. Low 67°. Wind north-northeast around 7 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Sunday	Mostly sunny. Moderate fog in the morning. High 84°. UV index up to 9. Wind north-northeast around 9 mph, gusting to 27 mph.
Sunday night	Fair in the evening, becoming clear after midnight. Relatively cool. Low 66°. Wind north-northeast around 5 mph, gusting to 23 mph.
Monday	Sunny. High 88°. Heat index up to 91°. UV index up to 9. Wind north around 6 mph, gusting to 26 mph, in the morning, becoming 9 mph, gusting to 27 mph, in the afternoon.
Monday night	Clear. Relatively cool. Low 66°. Wind north-northeast around 4 mph, gusting to 23 mph.
Tuesday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. High 89°. Heat index up to 93°. UV index up to 8. Wind northeast around 4 mph, gusting to 24 mph, in the morning, becoming 8 mph, gusting to 25 mph, in the afternoon.
Tuesday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 69°. Wind northeast around 3 mph, gusting to 19 mph.
Wednesday	Partly to mostly sunny in the morning, becoming mostly cloudy in the afternoon. A slight chance of rain. Scattered thunderstorms likely. High 89°. Heat index up to 94°. UV index up to 7. Wind northeast around 4 mph, gusting to 23 mph, in the morning, becoming east in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Partly to mostly cloudy in the evening, becoming mostly clear after midnight. Light to moderate fog after midnight. Low 71°. Wind south around 2 mph, gusting to 15 mph.
Thursday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. Hot. High 92°. Heat index up to 99°. UV index up to 9. Wind west around 5 mph, gusting to 23 mph.
Thursday night	Mostly clear in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 72°. Wind west around 5 mph, gusting to 20 mph.
Friday	Sunny. Patchy light fog in the morning. Hot. High 92°. Heat index up to 101°. UV index up to 9. Wind west around 7 mph, gusting to 27 mph, in the morning, becoming 11 mph, gusting to 28 mph, in the afternoon.
Friday night	Fair in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 72°. Wind west-southwest around 6 mph, gusting to 21 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

Powered by Davis Vantage Pro2 and CumulusMX v 4.6.4 (b4128) MXUI Template v 2.2.6 by Silver Acorn Valid HTML5