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, 04-Sep-2026 05:00 am

Today Sunny Hot!	Tonight Fair	Saturday Partly Cloudy Hot!	Saturday night Fog late	Sunday Fog a.m.	Sunday night Partly Cloudy	Monday Sunny	Monday night Mostly Clear

High: 102°	Low: 76°	High: 99°	Low: 71°	High: 92°	Low: 67°	High: 92°	Low: 65°
Heat: 110°		Heat: 108°		Heat: 97°
SSW 4-25 mph	SSW 2-18 mph	W→NNW 4-21 mph	N 3 mph	ENE 6-24 mph	ENE 6-20 mph	E 5-24 mph	ESE 5-19 mph
UV: 8 Very High		UV: 7 High		UV: 6 High		UV: 8 Very High

Today	Sunny. Near record heat. High 102°. Heat index up to 110°. UV index up to 8. Wind south-southwest around 4 mph, gusting to 25 mph.
Tonight	Fair. Warm. Low 76°. Wind south-southwest around 2 mph, gusting to 18 mph.
Saturday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Extremely hot. High 99°. Heat index up to 108°. UV index up to 7. Wind west around 4 mph, gusting to 21 mph, in the morning, becoming north-northwest in the afternoon.
Saturday night	Fair to partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 71°. Wind north around 3 mph.
Sunday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Very hot. High 92°. Heat index up to 97°. UV index up to 6. Wind east-northeast around 6 mph, gusting to 24 mph.
Sunday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 67°. Wind east-northeast around 6 mph, gusting to 20 mph.
Monday	Sunny. Very hot. High 92°. UV index up to 8. Wind east around 5 mph, gusting to 24 mph.
Monday night	Mostly clear in the evening, becoming clear after midnight. Low 65°. Wind east-southeast around 5 mph, gusting to 19 mph.
Tuesday	Sunny. Patchy light fog in the morning. Very hot. High 95°. Heat index up to 98°. UV index up to 7. Wind south-southeast around 4 mph, gusting to 22 mph.
Tuesday night	Clear. Low 68°. Wind south-southeast around 6 mph, gusting to 15 mph.
Wednesday	Sunny in the morning, becoming mostly sunny in the afternoon. Extremely hot. High 100°. Heat index up to 105°. UV index up to 8. Wind west-southwest around 7 mph, gusting to 23 mph.
Wednesday night	Partly cloudy. Low 69°. Wind northeast around 4 mph.
Thursday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 94°. Heat index up to 98°. UV index up to 7. Wind northeast around 5 mph, gusting to 21 mph.
Thursday night	Mostly clear. Low 65°. Wind northeast around 7 mph, gusting to 15 mph, in the evening, becoming east-southeast after midnight.

WXSIM forecast formatting script by Saratoga-Weather.org.

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