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 04:00 pm

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

Low: 76°	High: 97°	Low: 71°	High: 90°	Low: 65°	High: 89°	Low: 63°	High: 92°
	Heat: 107°		Heat: 94°
SSW 3-19 mph	WNW→NNW 4-22 mph	NE 4-16 mph	NE 6-24 mph	NE→E 6-21 mph	E 5-24 mph	E 4-18 mph	SE 4-23 mph
	UV: 8 Very High		UV: 8 Very High		UV: 8 Very High		UV: 7 High

Tonight	Clear in the evening, becoming fair to partly cloudy after midnight. Warm. Low 76°. Wind south-southwest around 3 mph, gusting to 19 mph.
Saturday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 97°. Heat index up to 107°. UV index up to 8. Wind west-northwest around 4 mph, gusting to 22 mph, in the morning, becoming north-northwest in the afternoon.
Saturday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 71°. Wind northeast around 4 mph, gusting to 16 mph.
Sunday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Hot. High 90°. Heat index up to 94°. UV index up to 8. Wind northeast around 6 mph, gusting to 24 mph.
Sunday night	Partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 65°. Wind northeast around 6 mph, gusting to 21 mph, in the evening, becoming east after midnight.
Monday	Sunny. Patchy light fog in the morning. Hot. High 89°. UV index up to 8. Wind east around 5 mph, gusting to 24 mph.
Monday night	Mostly clear in the evening, becoming fair to partly cloudy after midnight. Low 63°. Wind east around 4 mph, gusting to 18 mph.
Tuesday	Sunny. Patchy light fog in the morning. Very hot. High 92°. UV index up to 7. Wind southeast around 4 mph, gusting to 23 mph.
Tuesday night	Clear in the evening, becoming fair to partly cloudy after midnight. Low 68°. Wind southeast around 6 mph, gusting to 15 mph, in the evening, becoming south after midnight.
Wednesday	Sunny in the morning, becoming mostly sunny in the afternoon. Very hot. High 95°. Heat index up to 99°. UV index up to 7. Wind west-southwest around 6 mph, gusting to 21 mph.
Wednesday night	Fair to 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 rain likely after midnight. Low 66°. Wind north around 3 mph. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Thursday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Light to moderate fog in the morning. A chance of rain. Hot. High 87°. UV index up to 6. Wind north-northeast around 4 mph, gusting to 20 mph. Chance of precipitation 40 percent. Precipitation mostly less than a quarter of an inch.
Thursday night	Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Low 63°. Wind east-northeast around 5 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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