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, 13-Sep-2026 05:00 am

Today Partly Cloudy	Tonight Partly Cloudy	Monday Partly Cloudy	Monday night Partly Cloudy	Tuesday Mostly Sunny	Tuesday night Thunder storm	Wednesday Fog a.m.	Wednesday night Partly Cloudy
					<.1 in.
High: 89°	Low: 59°	High: 86°	Low: 60°	High: 97°	Low: 65°	High: 94°	Low: 70°
						Heat: 98°
N 4-25 mph	NE 5-23 mph	ESE 8-26 mph	SE 8-20 mph	S→SW 7-23 mph	NE 3 mph	E→SSW 4-22 mph	SE→SSW 5 mph
UV: 6 High		UV: 6 High		UV: 7 High		UV: 7 High

Today	Partly cloudy. Unusually hot. High 89°. UV index up to 6. Wind north around 4 mph, gusting to 25 mph.
Tonight	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 59°. Wind northeast around 5 mph, gusting to 23 mph.
Monday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Hot. High 86°. UV index up to 6. Wind east-southeast around 8 mph, gusting to 26 mph.
Monday night	Partly cloudy in the evening, becoming mostly clear after midnight. Low 60°. Wind southeast around 8 mph, gusting to 20 mph.
Tuesday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Extremely hot. High 97°. UV index up to 7. Wind south around 7 mph, gusting to 23 mph, in the morning, becoming southwest in the afternoon.
Tuesday night	Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. A chance of rain. Scattered thundershowers possible. Low 65°. Wind northeast around 3 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 94°. Heat index up to 98°. UV index up to 7. Wind east around 4 mph, gusting to 22 mph, in the morning, becoming south-southwest in the afternoon.
Wednesday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Warm. Low 70°. Wind southeast around 5 mph in the evening, becoming south-southwest after midnight.
Thursday	Partly to mostly cloudy. A chance of rain. Scattered thunderstorms likely. Very hot. High 92°. Heat index up to 95°. UV index up to 5. Wind west-southwest around 4 mph, gusting to 22 mph, in the morning, becoming northwest in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 63°. Wind north-northeast around 3 mph, gusting to 15 mph.
Friday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 89°. UV index up to 7. Wind east-northeast around 5 mph, gusting to 22 mph.
Friday night	Fair in the evening, becoming mostly clear after midnight. Light to moderate fog in the evening, then moderate fog after midnight. Low 64°. Wind east-southeast around 5 mph.
Saturday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. Very hot. High 92°. Heat index up to 97°. UV index up to 4. Wind south around 8 mph, gusting to 21 mph, in the morning, becoming southwest in the afternoon.
Saturday night	Partly cloudy in the evening, becoming cloudy after midnight. Light to moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Scattered thunderstorms likely. Low 69°. Wind south-southwest around 5 mph, gusting to 18 mph, in the evening, becoming north-northwest after midnight. Chance of precipitation 60 percent. Precipitation mostly between a quarter and half an inch.

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