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: Saturday, 21-Mar-2026 04:00 pm

Tonight Mostly Clear	Sunday Mostly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Mostly Cloudy	Tuesday Partly Cloudy	Tuesday night Partly Cloudy	Wednesday Partly Cloudy

Low: 56°	High: 87°	Low: 40°	High: 59°	Low: 37°	High: 66°	Low: 40°	High: 76°

SSE→SSW 6-21 mph	SSW→NNW 8-30 mph	NNW 11-30 mph	NNE 7-27 mph	ENE 5-20 mph	ESE 6-25 mph	SSE 6-20 mph	SSW 7-25 mph
	UV: 5 Medium		UV: 5 Medium		UV: 5 Medium		UV: 6 High

Tonight	Clear in the evening, becoming mostly clear after midnight. Relatively mild. Low 56°. Wind south-southeast around 6 mph, gusting to 21 mph, in the evening, becoming south-southwest after midnight.
Sunday	Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Exceptionally hot. High 87°. UV index up to 5. Wind south-southwest around 8 mph, gusting to 30 mph, in the morning, becoming north-northwest in the afternoon.
Sunday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 40°. Wind north-northwest around 11 mph, gusting to 30 mph.
Monday	Partly cloudy. High 59°. UV index up to 5. Wind north-northeast around 7 mph, gusting to 27 mph.
Monday night	Partly to mostly cloudy. Low 37°. Wind east-northeast around 5 mph, gusting to 20 mph.
Tuesday	Sunny in the morning, becoming partly cloudy in the afternoon. Mild. High 66°. UV index up to 5. Wind east-southeast around 6 mph, gusting to 25 mph.
Tuesday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 40°. Wind south-southeast around 6 mph, gusting to 20 mph.
Wednesday	Partly cloudy. Unusually warm. High 76°. UV index up to 6. Wind south-southwest around 7 mph, gusting to 25 mph.
Wednesday night	Partly to mostly cloudy in the evening, becoming mostly clear after midnight. Low 47°. Wind south-southwest around 5 mph, gusting to 17 mph.
Thursday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Near record warmth. High 90°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 24 mph, in the morning, becoming 12 mph, gusting to 29 mph, in the afternoon.
Thursday night	Partly cloudy in the evening, becoming dense overcast after midnight. Patchy light fog after midnight. A slight chance of rain in the evening, then rain likely after midnight. Scattered thundershowers possible. Low 49°. Wind north around 8 mph, gusting to 18 mph, in the evening, becoming 11 mph, gusting to 22 mph, after midnight. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Friday	Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Rain likely in the morning, then a slight chance of rain in the afternoon. High 54°. UV index up to 5. Wind northeast around 10 mph, gusting to 28 mph. Chance of precipitation 70 percent. Precipitation mostly between half an inch and one inch.
Friday night	Clear in the evening, becoming mostly clear after midnight. Low 38°. Wind north-northwest around 4 mph, gusting to 24 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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