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: Wednesday, 18-Mar-2026 05:00 am

Today Mostly Sunny	Tonight Partly Cloudy	Thursday Partly Cloudy	Thursday night Partly Cloudy	Friday Sunny	Friday night Partly Cloudy	Saturday Sunny	Saturday night Clear

High: 64°	Low: 42°	High: 74°	Low: 42°	High: 79°	Low: 46°	High: 82°	Low: 48°

SSE→WSW 7-28 mph	SSW 2-18 mph	WSW→E 3-21 mph	ENE→WSW calm	W 3-18→8-24 mph	W 6-17→2 mph	WSW 3-22 mph	SSW 4→7 mph
UV: 4 Medium		UV: 5 Medium		UV: 6 High		UV: 6 High

Today	Partly to mostly sunny. Mild. High 64°. UV index up to 4. Wind south-southeast around 7 mph, gusting to 28 mph, in the morning, becoming west-southwest in the afternoon.
Tonight	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Low 42°. Wind south-southwest around 2 mph, gusting to 18 mph.
Thursday	Partly cloudy in the morning, becoming mostly sunny in the afternoon. Unusually warm. High 74°. UV index up to 5. Wind west-southwest around 3 mph, gusting to 21 mph, in the morning, becoming east in the afternoon.
Thursday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 42°. Wind east-northeast near calm in the evening, becoming west-southwest after midnight.
Friday	Sunny. Unusually warm. High 79°. UV index up to 6. Wind west around 3 mph, gusting to 18 mph, in the morning, becoming 8 mph, gusting to 24 mph, in the afternoon.
Friday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 46°. Wind west around 6 mph, gusting to 17 mph, in the evening, becoming 2 mph after midnight.
Saturday	Sunny. Unusually hot. High 82°. UV index up to 6. Wind west-southwest around 3 mph, gusting to 22 mph.
Saturday night	Clear. Low 48°. Wind south-southwest around 4 mph in the evening, becoming 7 mph after midnight.
Sunday	Sunny in the morning, becoming partly to mostly cloudy in the afternoon. Unusually warm. High 79°. UV index up to 5. Wind south-southwest around 6 mph, gusting to 22 mph, in the morning, becoming north around 11 mph, gusting to 28 mph, in the afternoon.
Sunday night	Partly to mostly cloudy in the evening, becoming fair after midnight. A slight chance of rain. Low 39°. Wind north around 11 mph, gusting to 27 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday	Mostly sunny in the morning, becoming sunny in the afternoon. High 61°. UV index up to 6. Wind north around 8 mph, gusting to 27 mph.
Monday night	Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. Low 39°. Wind north-northeast around 5 mph, gusting to 21 mph, in the evening, becoming east-northeast after midnight.
Tuesday	Cloudy. High 53°. Wind east-southeast around 9 mph, gusting to 26 mph.
Tuesday night	Cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Low 42°. Wind east-southeast around 7 mph, gusting to 24 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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