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, 05-Sep-2026 05:00 am

Today Partly Cloudy Hot!	Tonight Clear	Sunday Mostly Sunny	Sunday night Partly Cloudy	Monday Sunny	Monday night Partly Cloudy	Tuesday Sunny	Tuesday night Clear

High: 103°	Low: 74°	High: 94°	Low: 68°	High: 91°	Low: 64°	High: 93°	Low: 67°
Heat: 111°		Heat: 99°
S→NNW 4-24 mph	NE 4-18 mph	NE 6-26 mph	ENE 6-23 mph	E 5-25 mph	ESE 4-19 mph	SE 4-23 mph	SSE 5-16 mph
UV: 7 High		UV: 8 Very High		UV: 8 Very High		UV: 7 High

Today	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Near record heat. High 103°. Heat index up to 111°. UV index up to 7. Wind south around 4 mph, gusting to 24 mph, in the morning, becoming north-northwest in the afternoon.
Tonight	Fair in the evening, becoming clear after midnight. Warm. Low 74°. Wind northeast around 4 mph, gusting to 18 mph.
Sunday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 94°. Heat index up to 99°. UV index up to 8. Wind northeast around 6 mph, gusting to 26 mph.
Sunday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 68°. Wind east-northeast around 6 mph, gusting to 23 mph.
Monday	Sunny. Very hot. High 91°. UV index up to 8. Wind east around 5 mph, gusting to 25 mph.
Monday night	Clear in the evening, becoming fair to partly cloudy after midnight. Low 64°. Wind east-southeast around 4 mph, gusting to 19 mph.
Tuesday	Sunny. Very hot. High 93°. UV index up to 7. Wind southeast around 4 mph, gusting to 23 mph.
Tuesday night	Clear. Low 67°. Wind south-southeast around 5 mph, gusting to 16 mph.
Wednesday	Mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 97°. Heat index up to 102°. UV index up to 7. Wind southwest around 6 mph, gusting to 20 mph.
Wednesday night	Fair to partly cloudy in the evening, becoming mostly cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Low 68°. Wind north-northeast around 4 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Partly to mostly cloudy. A chance of rain in the morning, then a slight chance of rain in the afternoon. Warm. High 84°. UV index up to 5. Wind north-northeast around 4 mph, gusting to 22 mph. Chance of precipitation 50 percent. Precipitation mostly around a quarter of an inch.
Thursday night	Mostly cloudy to cloudy in the evening, becoming dense overcast after midnight. Light to moderate fog. Rain likely. Low 68°. Wind east-northeast around 5 mph, gusting to 18 mph. Chance of precipitation 80 percent. Precipitation mostly around an inch.
Friday	Dense overcast in the morning, becoming 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 74°. Wind east around 7 mph, gusting to 21 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Friday night	Mostly cloudy in the evening, becoming partly to mostly cloudy after midnight. Light to moderate fog after midnight. A chance of rain. Low 64°. Wind east around 4 mph, gusting to 17 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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