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, 15-Aug-2026 05:00 am

Today Chance rain Hot!	Tonight Chance rain	Sunday Thunder storm Hot!	Sunday night Thunder storm	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Partly Cloudy
.1 in.	.1 in.	<.1 in.	.1 in.	<.1 in.
High: 97°	Low: 78°	High: 97°	Low: 73°	High: 86°	Low: 68°	High: 90°	Low: 72°
Heat: 110°		Heat: 111°				Heat: 96°
SSW 5-24 mph	SW 3-15 mph	SW 5-23 mph	NNW 5-18 mph	NNW 5-23 mph	NE 2-20 mph	SSE 3-21 mph	ESE 4-15 mph
UV: 7 High		UV: 8 Very High		UV: 8 Very High		UV: 8 Very High

Today	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. A chance of rain. Very hot. High 97°. Heat index up to 110°. UV index up to 7. Wind south-southwest around 5 mph, gusting to 24 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Tonight	Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A chance of rain. Warm. Low 78°. Wind southwest around 3 mph, gusting to 15 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Sunday	Partly cloudy. A slight chance of rain in the morning, then a chance of rain in the afternoon. Scattered thundershowers possible. Very hot. High 97°. Heat index up to 111°. UV index up to 8. Wind southwest around 5 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Mostly cloudy in the evening, becoming fair to partly cloudy after midnight. Patchy light fog in the evening, then moderate fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Scattered thundershowers possible. Low 73°. Wind north-northwest around 5 mph, gusting to 18 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Monday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Moderate fog in the morning. A slight chance of rain. High 86°. UV index up to 8. Wind north-northwest around 5 mph, gusting to 23 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Partly cloudy. Patchy light fog after midnight. Low 68°. Wind northeast around 2 mph, gusting to 20 mph.
Tuesday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. Hot. High 90°. Heat index up to 96°. UV index up to 8. Wind south-southeast around 3 mph, gusting to 21 mph.
Tuesday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 72°. Wind east-southeast around 4 mph, gusting to 15 mph.
Wednesday	Partly cloudy. Hot. High 91°. Heat index up to 95°. UV index up to 8. Wind north around 5 mph, gusting to 24 mph.
Wednesday night	Mostly cloudy to cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A chance of rain in the evening, then a slight chance of rain after midnight. Precipitation showery or intermittent. Low 68°. Wind northeast around 4 mph, gusting to 18 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. High 82°. UV index up to 6. Wind east around 4 mph, gusting to 21 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch.
Thursday night	Mostly cloudy to cloudy in the evening, becoming partly cloudy after midnight. Light to moderate fog after midnight. A chance of rain. Precipitation showery or intermittent. Low 69°. Wind east around 4 mph, gusting to 19 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.
Friday	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain. Precipitation showery or intermittent. High 82°. UV index up to 5. Wind east around 5 mph, gusting to 23 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Friday night	Fair to partly cloudy in the evening, becoming clear after midnight. Moderate fog after midnight. Low 65°. Wind northeast around 4 mph, gusting to 22 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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