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: Saturday, 19-Sep-2026 05:00 am

Today Partly Cloudy Hot!	Tonight Partly Cloudy	Sunday Mostly Cloudy	Sunday night Chance rain	Monday Chance rain	Monday night Chance rain	Tuesday Fog a.m.	Tuesday night Cloudy
			<.25 in.	<.1 in.	<.1 in.	<.1 in.
High: 100°	Low: 74°	High: 93°	Low: 68°	High: 77°	Low: 64°	High: 71°	Low: 60°
Heat: 107°		Heat: 98°
SW 6-26 mph	SE→WSW 3-19 mph	W 3-22 mph	N→NE 5-20 mph	NE 5-23 mph	NE 6-23 mph	NNE 7-25 mph	NNE 6-24 mph
UV: 7 High		UV: 6 High		UV: 4 Medium

Today	Partly cloudy. Near record heat. High 100°. Heat index up to 107°. UV index up to 7. Wind southwest around 6 mph, gusting to 26 mph.
Tonight	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Warm. Low 74°. Wind southeast around 3 mph, gusting to 19 mph, in the evening, becoming west-southwest after midnight.
Sunday	Partly to mostly cloudy. Very hot. High 93°. Heat index up to 98°. UV index up to 6. Wind west around 3 mph, gusting to 22 mph.
Sunday night	Mostly cloudy in the evening, becoming cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Warm. Low 68°. Wind north around 5 mph, gusting to 20 mph, in the evening, becoming northeast after midnight. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Monday	Cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. Patchy light fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. High 77°. UV index up to 4. Wind northeast around 5 mph, gusting to 23 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Cloudy. Patchy light fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Low 64°. Wind northeast around 6 mph, gusting to 23 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Tuesday	Cloudy. Patchy light fog in the morning. A chance of rain. High 71°. Wind north-northeast around 7 mph, gusting to 25 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Cloudy. Low 60°. Wind north-northeast around 6 mph, gusting to 24 mph.
Wednesday	Mostly cloudy in the morning, becoming partly cloudy in the afternoon. High 75°. UV index up to 5. Wind north-northeast around 7 mph, gusting to 25 mph.
Wednesday night	Fair in the evening, becoming partly cloudy after midnight. Low 55°. Wind north-northeast around 3 mph, gusting to 21 mph.
Thursday	Partly cloudy. High 78°. UV index up to 6. Wind north-northeast around 3 mph, gusting to 23 mph.
Thursday night	Mostly cloudy to cloudy in the evening, becoming dense overcast after midnight. Patchy light fog after midnight. A slight chance of rain in the evening, then rain likely after midnight. Low 60°. Wind northeast around 4 mph, gusting to 18 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch.
Friday	Dense overcast in the morning, becoming cloudy in the afternoon. Patchy light fog. Rain likely in the morning, then a chance of rain in the afternoon. High 66°. Wind east-northeast around 3 mph, gusting to 15 mph. Chance of precipitation 80 percent. Precipitation mostly around half an inch.
Friday night	Mostly cloudy to cloudy in the evening, becoming cloudy after midnight. Low 60°. Wind east-northeast near calm.

WXSIM forecast formatting script by Saratoga-Weather.org.

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