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: Thursday, 19-Mar-2026 05:00 am

Today Mostly Cloudy	Tonight Partly Cloudy	Friday Mostly Sunny	Friday night Fog late	Saturday Fog a.m.	Saturday night Clear	Sunday Mostly Sunny	Sunday night Mostly Clear

High: 77°	Low: 46°	High: 84°	Low: 45°	High: 80°	Low: 51°	High: 79°	Low: 37°

SW 3-23 mph	SW 2 mph	WSW 5-18→9-26 mph	NW→NE 3-19 mph	ESE→S 3-21 mph	S 5→8 mph	SW→NW 9-23→13-29 mph	N 11-28 mph
UV: 5 Medium		UV: 6 High		UV: 6 High		UV: 6 High

Today	Partly to mostly cloudy in the morning, becoming mostly sunny in the afternoon. Unusually warm. High 77°. UV index up to 5. Wind southwest around 3 mph, gusting to 23 mph.
Tonight	Fair in the evening, becoming fair to partly cloudy after midnight. Low 46°. Wind southwest around 2 mph.
Friday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Exceptionally hot. High 84°. UV index up to 6. Wind west-southwest around 5 mph, gusting to 18 mph, in the morning, becoming 9 mph, gusting to 26 mph, in the afternoon.
Friday night	Partly cloudy in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 45°. Wind northwest around 3 mph, gusting to 19 mph, in the evening, becoming northeast after midnight.
Saturday	Sunny. Patchy light fog in the morning. Unusually warm. High 80°. UV index up to 6. Wind east-southeast around 3 mph, gusting to 21 mph, in the morning, becoming south in the afternoon.
Saturday night	Clear in the evening, becoming fair after midnight. Low 51°. Wind south around 5 mph in the evening, becoming 8 mph after midnight.
Sunday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Unusually warm. High 79°. UV index up to 6. Wind southwest around 9 mph, gusting to 23 mph, in the morning, becoming northwest around 13 mph, gusting to 29 mph, in the afternoon.
Sunday night	Clear in the evening, becoming mostly clear after midnight. Breezy. Low 37°. Wind north around 11 mph, gusting to 28 mph.
Monday	Sunny. High 60°. UV index up to 5. Wind north-northeast around 7 mph, gusting to 26 mph.
Monday night	Mostly clear in the evening, becoming partly cloudy after midnight. Low 37°. Wind east around 5 mph, gusting to 21 mph.
Tuesday	Partly cloudy. Mild. High 67°. UV index up to 5. Wind southeast around 7 mph, gusting to 24 mph.
Tuesday night	Mostly cloudy in the evening, becoming cloudy after midnight. Low 47°. Wind southeast around 6 mph, gusting to 22 mph.
Wednesday	Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Unusually warm. High 79°. UV index up to 5. Wind south around 7 mph, gusting to 17 mph, in the morning, becoming 10 mph, gusting to 26 mph, in the afternoon.
Wednesday night	Clear. Breezy. Low 52°. Wind south around 12 mph, gusting to 22 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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