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, 17-Sep-2026 05:00 am

Today Mostly Sunny Hot!	Tonight Partly Cloudy	Friday Mostly Sunny Hot!	Friday night Clear	Saturday Partly Cloudy Hot!	Saturday night Partly Cloudy	Sunday Mostly Cloudy	Sunday night Chance rain
							<.25 in.
High: 101°	Low: 72°	High: 96°	Low: 70°	High: 97°	Low: 69°	High: 92°	Low: 64°
Heat: 110°		Heat: 102°		Heat: 103°
SSW→W 5-26 mph	W→N 2-18 mph	ENE→ESE 3-23 mph	SE 3 mph	SW 5-24 mph	SSW→W calm→4 4	WNW 3-19 mph	NNE 5-15 mph
UV: 6 High		UV: 7 High		UV: 7 High		UV: 6 High

Today	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Near record heat. High 101°. Heat index up to 110°. UV index up to 6. Wind south-southwest around 5 mph, gusting to 26 mph, in the morning, becoming west in the afternoon.
Tonight	Fair to partly cloudy in the evening, becoming clear after midnight. Warm. Low 72°. Wind west around 2 mph, gusting to 18 mph, in the evening, becoming north after midnight.
Friday	Sunny in the morning, becoming mostly sunny in the afternoon. Extremely hot. High 96°. Heat index up to 102°. UV index up to 7. Wind east-northeast around 3 mph, gusting to 23 mph, in the morning, becoming east-southeast in the afternoon.
Friday night	Fair in the evening, becoming clear after midnight. Warm. Low 70°. Wind southeast around 3 mph.
Saturday	Sunny in the morning, becoming partly cloudy in the afternoon. Extremely hot. High 97°. Heat index up to 103°. UV index up to 7. Wind southwest around 5 mph, gusting to 24 mph.
Saturday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Warm. Low 69°. Wind south-southwest near calm in the evening, becoming west around 4 mph after midnight.
Sunday	Partly to mostly cloudy. Very hot. High 92°. UV index up to 6. Wind west-northwest around 3 mph, gusting to 19 mph.
Sunday night	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Light to moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Low 64°. Wind north-northeast around 5 mph, gusting to 15 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Monday	Partly cloudy. Moderate fog in the morning. A chance of rain. High 79°. UV index up to 6. Wind north-northeast around 4 mph, gusting to 18 mph, in the morning, becoming north-northwest in the afternoon. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Monday night	Partly to mostly cloudy in the evening, becoming cloudy after midnight. Light to moderate fog. A chance of rain in the evening, then a slight chance of rain after midnight. Low 64°. Wind north-northwest around 6 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Tuesday	Cloudy. Patchy light fog in the morning. A slight chance of rain. High 72°. Wind north-northwest around 6 mph, gusting to 24 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Mostly cloudy to cloudy in the evening, becoming fair to partly cloudy after midnight. Light to moderate fog after midnight. Low 56°. Wind north around 5 mph, gusting to 21 mph.
Wednesday	Sunny in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. High 77°. UV index up to 6. Wind north around 5 mph, gusting to 23 mph.
Wednesday night	Partly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Low 58°. Wind north-northeast around 5 mph, gusting to 18 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

Powered by Davis Vantage Pro2 and CumulusMX v 4.6.4 (b4128) MXUI Template v 2.2.6 by Silver Acorn Valid HTML5