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, 18-Oct-2026 04:00 pm

Tonight Fair	Monday Partly Cloudy	Monday night Partly Cloudy	Tuesday Partly Cloudy	Tuesday night Clear	Wednesday Sunny	Wednesday night Fog late	Thursday Fog a.m.

Low: 42°	High: 68°	Low: 46°	High: 70°	Low: 43°	High: 70°	Low: 43°	High: 70°

SSE 3-21 mph	SSE 2-20 mph	E→SE 2 mph	SE 2-19 mph	SE 2 mph	S→SE 1-18 mph	ESE→N calm	E 1-17 mph
	UV: 4 Medium		UV: 4 Medium		UV: 5 Medium		UV: 4 Medium

Tonight	Fair. Low 42°. Wind south-southeast around 3 mph, gusting to 21 mph.
Monday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. High 68°. UV index up to 4. Wind south-southeast around 2 mph, gusting to 20 mph.
Monday night	Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Low 46°. Wind east around 2 mph in the evening, becoming southeast after midnight.
Tuesday	Partly cloudy in the morning, becoming sunny in the afternoon. Mild. High 70°. UV index up to 4. Wind southeast around 2 mph, gusting to 19 mph.
Tuesday night	Clear. Low 43°. Wind southeast around 2 mph.
Wednesday	Sunny. Mild. High 70°. UV index up to 5. Wind south around 1 mph, gusting to 18 mph, in the morning, becoming southeast in the afternoon.
Wednesday night	Clear. Patchy light fog after midnight. Low 43°. Wind east-southeast near calm in the evening, becoming north after midnight.
Thursday	Sunny. Patchy light fog in the morning. Mild. High 70°. UV index up to 4. Wind east around 1 mph, gusting to 17 mph.
Thursday night	Clear in the evening, becoming mostly clear after midnight. Low 46°. Wind east-southeast around 2 mph.
Friday	Sunny. Patchy light fog in the morning. Warm. High 73°. UV index up to 4. Wind southeast around 5 mph, gusting to 23 mph.
Friday night	Fair in the evening, becoming partly cloudy after midnight. Low 49°. Wind southeast around 5 mph.
Saturday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Warm. High 77°. Wind south-southeast around 6 mph, gusting to 22 mph.
Saturday night	Partly cloudy. Low 50°. Wind south around 4 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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