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, 15-Mar-2026 04:00 pm

Tonight Severe storm	Monday Cloudy	Monday night Partly Cloudy	Tuesday Partly Cloudy	Tuesday night Mix	Wednesday Sunny	Wednesday night Partly Cloudy	Thursday Partly Cloudy
.25 in.				<.1 in.
Low: 26°	High: 28°	Low: 11°	High: 39°	Low: 32°	High: 64°	Low: 39°	High: 70°
WCh: 19°	WCh: 5°	WCh: -1°		WCh: 25°
WNW 17-34 mph	WNW 17-34 mph	WNW 10-24 mph	NW→SW 7-22→4-22 mph	SE 8-23 mph	S→WSW 7-24 mph	WSW→SSW 3-18 mph	WSW→NW 4-21 mph
					UV: 5 Medium		UV: 5 Medium

Tonight	Cloudy in the evening, becoming dense overcast after midnight. Patchy light fog in the evening. Rain likely in the evening, then a slight chance of a mix of rain and snow after midnight. Severe thunderstorms likely, with possible tornados. Windy and cold. Low 26°. Wind chill ranging from 19 to 57. Wind west-northwest around 17 mph, gusting to 34 mph. Chance of precipitation 70 percent. Precipitation (liquid equivalent) mostly around a quarter of an inch. No snow accumulation expected.
Monday	Dense overcast in the morning, becoming cloudy in the afternoon. Windy and very cold. High 28°, but temperatures falling in the afternoon. Wind chill ranging from 5 to 18. Wind west-northwest around 17 mph, gusting to 34 mph.
Monday night	Partly cloudy in the evening, becoming fair after midnight. Extremely cold. Low 11°. Wind chill ranging from -1 to 5. Wind west-northwest around 10 mph, gusting to 24 mph.
Tuesday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Cold. High 39°. Wind northwest around 7 mph, gusting to 22 mph, in the morning, becoming southwest around 4 mph, gusting to 22 mph, in the afternoon.
Tuesday night	Cloudy in the evening, becoming mostly cloudy to cloudy after midnight. A chance of a mix of sleet and snow. Low 32°. Wind chill ranging from 25 to 34. Wind southeast around 8 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation (liquid equivalent) mostly less than a tenth of an inch. No snow or ice (on ground) accumulation expected.
Wednesday	Sunny. Mild. High 64°. UV index up to 5. Wind south around 7 mph, gusting to 24 mph, in the morning, becoming west-southwest in the afternoon.
Wednesday night	Partly cloudy. Low 39°. Wind west-southwest around 3 mph, gusting to 18 mph, in the evening, becoming south-southwest after midnight.
Thursday	Partly cloudy in the morning, becoming sunny in the afternoon. Mild. High 70°. UV index up to 5. Wind west-southwest around 4 mph, gusting to 21 mph, in the morning, becoming northwest in the afternoon.
Thursday night	Clear. Low 39°. Wind northeast around 2 mph in the evening, becoming south-southwest after midnight.
Friday	Sunny. Unusually warm. High 75°. UV index up to 6. Wind south-southwest around 3 mph, gusting to 17 mph, in the morning, becoming 7 mph, gusting to 23 mph, in the afternoon.
Friday night	Fair. Low 43°. Wind south-southwest around 5 mph, gusting to 16 mph.
Saturday	Sunny. Unusually hot. High 82°. UV index up to 6. Wind west-northwest around 6 mph, gusting to 22 mph.
Saturday night	Clear. Low 44°. Wind south-southwest around 4 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