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, 16-Sep-2026 05:00 am

Today Partly Cloudy Hot!	Tonight Fog late	Thursday Fog a.m. Hot!	Thursday night Partly Cloudy	Friday Mostly Sunny Hot!	Friday night Fog late	Saturday Partly Cloudy Hot!	Saturday night Partly Cloudy

High: 100°	Low: 71°	High: 100°	Low: 70°	High: 95°	Low: 67°	High: 96°	Low: 69°
Heat: 108°		Heat: 108°		Heat: 101°		Heat: 100°
SSW 4-24 mph	SSW 4-16 mph	WSW 5-24 mph	WSW→NNE 2 mph	ENE→SSE 3-22 mph	SE 5-15 mph	SW 6-23 mph	SW 3 mph
UV: 6 High		UV: 7 High		UV: 7 High		UV: 6 High

Today	Partly cloudy. Near record heat. High 100°. Heat index up to 108°. UV index up to 6. Wind south-southwest around 4 mph, gusting to 24 mph.
Tonight	Partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Warm. Low 71°. Wind south-southwest around 4 mph, gusting to 16 mph.
Thursday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Near record heat. High 100°. Heat index up to 108°. UV index up to 7. Wind west-southwest around 5 mph, gusting to 24 mph.
Thursday night	Fair to partly cloudy in the evening, becoming clear after midnight. Warm. Low 70°. Wind west-southwest around 2 mph in the evening, becoming north-northeast after midnight.
Friday	Sunny in the morning, becoming mostly sunny in the afternoon. Very hot. High 95°. Heat index up to 101°. UV index up to 7. Wind east-northeast around 3 mph, gusting to 22 mph, in the morning, becoming south-southeast in the afternoon.
Friday night	Fair. Patchy light fog after midnight. Low 67°. Wind southeast around 5 mph, gusting to 15 mph.
Saturday	Partly cloudy. Extremely hot. High 96°. Heat index up to 100°. UV index up to 6. Wind southwest around 6 mph, gusting to 23 mph.
Saturday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Warm. Low 69°. Wind southwest around 3 mph.
Sunday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Extremely hot. High 96°. UV index up to 6. Wind south-southwest around 2 mph, gusting to 22 mph, in the morning, becoming northwest in the afternoon.
Sunday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 66°. Wind northeast around 4 mph.
Monday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. A slight chance of rain. Unusually hot. High 88°. UV index up to 5. Wind northwest around 4 mph, gusting to 24 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Clear. Light to moderate fog after midnight. Low 60°. Wind north around 3 mph, gusting to 19 mph.
Tuesday	Sunny in the morning, becoming mostly sunny in the afternoon. Light to moderate fog in the morning. Warm. High 85°. UV index up to 6. Wind north around 2 mph, gusting to 21 mph, in the morning, becoming east-southeast in the afternoon.
Tuesday night	Partly cloudy in the evening, becoming fair after midnight. Light to moderate fog after midnight. Low 62°. Wind south-southeast around 4 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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