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: Friday, 20-Mar-2026 04:00 pm

Tonight Fog late	Saturday Fog a.m.	Saturday night Mostly Clear	Sunday Mostly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Mostly Cloudy	Tuesday Partly Cloudy
						<.1 in.
Low: 46°	High: 81°	Low: 50°	High: 83°	Low: 39°	High: 59°	Low: 39°	High: 68°

NNW→ENE 3-26 mph	ESE→S 3-20 mph	S 4→8 mph	SSW→NNW 9-29 mph	NNW 12-29→9-25 mph	NNE 7-26 mph	ENE→ESE 5-22 mph	SE 5-25 mph
	UV: 6 High		UV: 5 Medium		UV: 5 Medium		UV: 6 High

Tonight	Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 46°. Wind north-northwest around 3 mph, gusting to 26 mph, in the evening, becoming east-northeast after midnight.
Saturday	Sunny. Patchy light fog in the morning. Unusually warm. High 81°. UV index up to 6. Wind east-southeast around 3 mph, gusting to 20 mph, in the morning, becoming south in the afternoon.
Saturday night	Clear in the evening, becoming mostly clear after midnight. Low 50°. Wind south around 4 mph in the evening, becoming 8 mph after midnight.
Sunday	Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Unusually hot. High 83°. UV index up to 5. Wind south-southwest around 9 mph, gusting to 29 mph, in the morning, becoming north-northwest in the afternoon.
Sunday night	Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Low 39°. Wind north-northwest around 12 mph, gusting to 29 mph, in the evening, becoming 9 mph, gusting to 25 mph, after midnight.
Monday	Partly cloudy. High 59°. UV index up to 5. Wind north-northeast around 7 mph, gusting to 26 mph.
Monday night	Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. A slight chance of rain after midnight. Low 39°. Wind east-northeast around 5 mph, gusting to 22 mph, in the evening, becoming east-southeast after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Mild. High 68°. UV index up to 6. Wind southeast around 5 mph, gusting to 25 mph.
Tuesday night	Partly cloudy. Low 42°. Wind southeast around 3 mph, gusting to 19 mph.
Wednesday	Mostly cloudy to cloudy. A slight chance of rain. Mild. High 67°. Wind southeast around 4 mph, gusting to 16 mph, in the morning, becoming 8 mph, gusting to 21 mph, in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Fair in the evening, becoming mostly clear after midnight. Low 44°. Wind south-southeast around 7 mph, gusting to 18 mph.
Thursday	Mostly sunny in the morning, becoming mostly cloudy in the afternoon. Breezy and unusually warm. High 77°. UV index up to 5. Wind southwest around 9 mph, gusting to 29 mph, in the morning, becoming north-northwest around 15 mph, gusting to 30 mph, in the afternoon.
Thursday night	Mostly clear in the evening, becoming clear after midnight. Breezy. Low 36°. Wind north around 11 mph, gusting to 28 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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