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, 11-Sep-2026 05:00 am

Today Mostly Cloudy	Tonight Partly Cloudy	Saturday Sunny	Saturday night Partly Cloudy	Sunday Mostly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Clear
<.1 in.
High: 82°	Low: 67°	High: 90°	Low: 66°	High: 87°	Low: 62°	High: 86°	Low: 61°
		Heat: 94°
E 4-22 mph	SE→S 4-19 mph	SW→W 4-23 mph	W calm	NNE 3-20 mph	NNE 6-18 mph	ENE→ESE 7-24 mph	ESE→SSE 7-19 mph
		UV: 6 High		UV: 5 Medium		UV: 6 High

Today	Mostly cloudy to cloudy. A chance of rain. Warm. High 82°. Wind east around 4 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tonight	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 67°. Wind southeast around 4 mph, gusting to 19 mph, in the evening, becoming south after midnight.
Saturday	Sunny. Unusually hot. High 90°. Heat index up to 94°. UV index up to 6. Wind southwest around 4 mph, gusting to 23 mph, in the morning, becoming west in the afternoon.
Saturday night	Fair in the evening, becoming partly cloudy after midnight. Low 66°. Wind west near calm.
Sunday	Mostly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Hot. High 87°. UV index up to 5. Wind north-northeast around 3 mph, gusting to 20 mph.
Sunday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 62°. Wind north-northeast around 6 mph, gusting to 18 mph.
Monday	Mostly cloudy in the morning, becoming partly cloudy in the afternoon. Hot. High 86°. UV index up to 6. Wind east-northeast around 7 mph, gusting to 24 mph, in the morning, becoming east-southeast in the afternoon.
Monday night	Clear. Low 61°. Wind east-southeast around 7 mph, gusting to 19 mph, in the evening, becoming south-southeast after midnight.
Tuesday	Mostly sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 95°. UV index up to 6. Wind south around 6 mph, gusting to 22 mph, in the morning, becoming southwest in the afternoon.
Tuesday night	Partly cloudy in the evening, becoming clear after midnight. Low 64°. Wind north around 2 mph in the evening, becoming southeast after midnight.
Wednesday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Very hot. High 96°. Heat index up to 99°. UV index up to 6. Wind southwest around 3 mph, gusting to 20 mph, in the morning, becoming west in the afternoon.
Wednesday night	Partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 66°. Wind east-southeast around 4 mph in the evening, becoming south-southeast after midnight.
Thursday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Extremely hot. High 97°. Heat index up to 102°. UV index up to 6. Wind south-southwest around 8 mph, gusting to 23 mph.
Thursday night	Fair to partly cloudy in the evening, becoming fair after midnight. Low 69°. Wind south-southwest around 4 mph.

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