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, 18-Sep-2026 05:00 am

Today Sunny Hot!	Tonight Partly Cloudy	Saturday Partly Cloudy Hot!	Saturday night Partly Cloudy	Sunday Chance rain	Sunday night Rain likely	Monday Chance rain	Monday night Chance rain
				.1 in.	.35 in.	.1 in.	<.1 in.
High: 97°	Low: 72°	High: 95°	Low: 71°	High: 89°	Low: 70°	High: 75°	Low: 61°
Heat: 103°		Heat: 101°		Heat: 93°
ENE→S 2-23 mph	SSE 4 mph	SW 6-24 mph	S→SW 2 mph	NW→W 3-21 mph	NE→NW 2 mph	NW 3-17→8-23 mph	N 7-22 mph
UV: 7 High		UV: 6 High		UV: 5 Medium

Today	Sunny. Extremely hot. High 97°. Heat index up to 103°. UV index up to 7. Wind east-northeast around 2 mph, gusting to 23 mph, in the morning, becoming south in the afternoon.
Tonight	Fair in the evening, becoming fair to partly cloudy after midnight. Warm. Low 72°. Wind south-southeast around 4 mph.
Saturday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Very hot. High 95°. Heat index up to 101°. UV index up to 6. Wind southwest around 6 mph, gusting to 24 mph.
Saturday night	Partly cloudy. Warm. Low 71°. Wind south around 2 mph in the evening, becoming southwest after midnight.
Sunday	Partly cloudy in the morning, becoming mostly cloudy in the afternoon. A chance of rain in the afternoon. Unusually hot. High 89°. Heat index up to 93°. UV index up to 5. Wind northwest around 3 mph, gusting to 21 mph, in the morning, becoming west in the afternoon. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Sunday night	Partly to mostly cloudy in the evening, becoming cloudy after midnight. Moderate fog in the evening, then patchy light fog after midnight. Rain likely. Warm. Low 70°. Wind northeast around 2 mph in the evening, becoming northwest after midnight. Chance of precipitation 60 percent. Precipitation mostly between a quarter and half 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. High 75°. Wind northwest around 3 mph, gusting to 17 mph, in the morning, becoming 8 mph, gusting to 23 mph, in the afternoon. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Monday night	Mostly cloudy in the evening, becoming cloudy after midnight. Patchy light fog after midnight. A chance of rain. Low 61°. Wind north around 7 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Tuesday	Cloudy. A slight chance of rain. High 69°. Wind north-northeast around 8 mph, gusting to 26 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 mostly cloudy after midnight. Low 56°. Wind north-northeast around 7 mph, gusting to 24 mph.
Wednesday	Partly to mostly cloudy. High 73°. UV index up to 5. Wind north-northeast around 8 mph, gusting to 26 mph.
Wednesday night	Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Low 57°. Wind north-northeast around 6 mph, gusting to 22 mph.
Thursday	Mostly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. High 74°. UV index up to 5. Wind northeast around 6 mph, gusting to 25 mph.
Thursday night	Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Low 56°. Wind northeast around 5 mph, gusting to 21 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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