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, 06-Sep-2026 04:00 pm

Tonight Partly Cloudy	Monday Fog a.m.	Monday night Partly Cloudy	Tuesday Partly Cloudy	Tuesday night Mostly Clear	Wednesday Thunder storm	Wednesday night Thunder storm	Thursday Fog a.m.
					.1 in.	.75 in.	<.1 in.
Low: 67°	High: 88°	Low: 63°	High: 94°	Low: 67°	High: 93°	Low: 70°	High: 84°
					Heat: 99°
ENE 6-21 mph	ENE 6-24 mph	E 4-18 mph	SSE 5-23 mph	SSE 6-17 mph	SSW→W 7-21 mph	WNW 3 mph	N 5-23 mph
	UV: 8 Very High		UV: 7 High		UV: 7 High		UV: 6 High

Tonight	Fair to partly cloudy. Low 67°. Wind east-northeast around 6 mph, gusting to 21 mph.
Monday	Sunny. Patchy light fog in the morning. Hot. High 88°. UV index up to 8. Wind east-northeast around 6 mph, gusting to 24 mph.
Monday night	Clear in the evening, becoming fair to partly cloudy after midnight. Low 63°. Wind east around 4 mph, gusting to 18 mph.
Tuesday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 94°. UV index up to 7. Wind south-southeast around 5 mph, gusting to 23 mph.
Tuesday night	Mostly clear. Low 67°. Wind south-southeast around 6 mph, gusting to 17 mph.
Wednesday	Partly to mostly sunny. 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 99°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 21 mph, in the morning, becoming west in the afternoon. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Wednesday night	Mostly cloudy in the evening, becoming cloudy after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Scattered thundershowers possible. Low 70°. Wind west-northwest around 3 mph. Chance of precipitation 70 percent. Precipitation mostly between half an inch and one inch.
Thursday	Mostly cloudy in the morning, becoming sunny in the afternoon. Light to moderate fog in the morning. A chance of rain. Precipitation showery or intermittent. Warm. High 84°. UV index up to 6. Wind north around 5 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Clear. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 18 mph, in the evening, becoming east after midnight.
Friday	Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Warm. High 85°. UV index up to 6. Wind southeast around 4 mph, gusting to 21 mph.
Friday night	Fair in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain. Low 68°. Wind south-southeast around 4 mph, gusting to 16 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday	Sunny. Patchy light fog in the morning. Very hot. High 91°. Heat index up to 97°. UV index up to 7. Wind south-southwest around 5 mph, gusting to 21 mph.
Saturday night	Clear. Patchy light fog after midnight. Low 69°. Wind southeast around 5 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