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: Tuesday, 15-Sep-2026 05:00 am

Today Partly Cloudy Hot!	Tonight Partly Cloudy	Wednesday Mostly Sunny Hot!	Wednesday night Fog late	Thursday Fog a.m. Hot!	Thursday night Partly Cloudy	Friday Mostly Sunny Hot!	Friday night Partly Cloudy
	<.1 in.
High: 102°	Low: 74°	High: 100°	Low: 71°	High: 100°	Low: 71°	High: 96°	Low: 68°
Heat: 108°		Heat: 107°		Heat: 107°		Heat: 102°
SSW 7-26 mph	E→S 2 mph	SW 3-24 mph	S 4 mph	SW→W 4-23 mph	NNE→ENE calm	E→WSW 3-20 mph	ESE→S 4 mph
UV: 6 High		UV: 6 High		UV: 7 High		UV: 7 High

Today	Sunny in the morning, becoming partly cloudy in the afternoon. Near record heat. High 102°. Heat index up to 108°. UV index up to 6. Wind south-southwest around 7 mph, gusting to 26 mph.
Tonight	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. A slight chance of rain. Warm. Low 74°. Wind east around 2 mph in the evening, becoming south after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Wednesday	Partly to mostly sunny. Near record heat. High 100°. Heat index up to 107°. UV index up to 6. Wind southwest around 3 mph, gusting to 24 mph.
Wednesday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Warm. Low 71°. Wind south around 4 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 107°. UV index up to 7. Wind southwest around 4 mph, gusting to 23 mph, in the morning, becoming west in the afternoon.
Thursday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Warm. Low 71°. Wind north-northeast near calm in the evening, becoming east-northeast after midnight.
Friday	Sunny in the morning, becoming mostly sunny in the afternoon. Extremely hot. High 96°. Heat index up to 102°. UV index up to 7. Wind east around 3 mph, gusting to 20 mph, in the morning, becoming west-southwest in the afternoon.
Friday night	Fair to partly cloudy in the evening, becoming fair after midnight. Low 68°. Wind east-southeast around 4 mph in the evening, becoming south after midnight.
Saturday	Partly cloudy. Extremely hot. High 97°. Heat index up to 102°. UV index up to 6. Wind southwest around 6 mph, gusting to 22 mph.
Saturday night	Fair in the evening, becoming fair to partly cloudy after midnight. Low 67°. Wind east-southeast around 3 mph in the evening, becoming west-southwest after midnight.
Sunday	Partly to mostly sunny. Extremely hot. High 97°. Heat index up to 101°. UV index up to 7. Wind southwest around 3 mph, gusting to 21 mph.
Sunday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Low 67°. Wind north around 3 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Monday	Cloudy. Patchy light fog in the morning. A chance of rain. Precipitation showery or intermittent. High 79°. Wind west around 4 mph, gusting to 20 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Monday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. Low 64°. Wind west-southwest around 3 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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