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, 05-Jun-2026 05:00 am

Today Thunder storm	Tonight Mostly Cloudy	Saturday Thunder storm	Saturday night Mostly Cloudy	Sunday Thunder storm	Sunday night Thunder storm	Monday Thunder storm	Monday night Thunder storm
<.1 in.	<.1 in.	<.1 in.	<.1 in.	<.25 in.	.1 in.	.5 in.	.5 in.
High: 86°	Low: 70°	High: 87°	Low: 72°	High: 80°	Low: 72°	High: 80°	Low: 73°

S 9-28 mph	SSW 7-22 mph	SSW 7-25 mph	SSW 4-22 mph	SSE 5-19 mph	SSE 6-17 mph	SSE→SSW 6-18 mph	S 5-16 mph
UV: 6 High		UV: 6 High		UV: 5 Medium		UV: 9 Very High

Today	Partly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. A slight chance of rain. Scattered thundershowers possible. High 86°. UV index up to 6. Wind south around 9 mph, gusting to 28 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tonight	Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Low 70°. Wind south-southwest around 7 mph, gusting to 22 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday	Mostly cloudy to cloudy. A slight chance of rain. Scattered thundershowers possible. Hot. High 87°. UV index up to 6. Wind south-southwest around 7 mph, gusting to 25 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Mostly cloudy to cloudy. A slight chance of rain. Precipitation showery or intermittent. Low 72°. Wind south-southwest around 4 mph, gusting to 22 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Sunday	Cloudy. Rain likely. Scattered thundershowers possible. High 80°. UV index up to 5. Wind south-southeast around 5 mph, gusting to 19 mph. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch.
Sunday night	Cloudy. Light to moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Scattered thunderstorms likely. Low 72°. Wind south-southeast around 6 mph, gusting to 17 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Monday	Partly to mostly cloudy. Moderate fog. Rain likely in the morning, then a chance of rain in the afternoon. Scattered thundershowers possible. High 80°. UV index up to 9. Wind south-southeast around 6 mph, gusting to 18 mph, in the morning, becoming south-southwest in the afternoon. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Monday night	Mostly cloudy. Moderate fog. Rain likely. Scattered thunderstorms likely. Low 73°. Wind south around 5 mph, gusting to 16 mph. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Tuesday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Moderate fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Precipitation showery or intermittent. Hot. High 89°. Heat index up to 99°. UV index up to 9. Wind south-southwest around 6 mph, gusting to 24 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Fair to partly cloudy in the evening, becoming fair after midnight. Light to moderate fog in the evening, then moderate fog after midnight. Low 74°. Wind south-southwest around 5 mph, gusting to 20 mph.
Wednesday	Partly to mostly cloudy in the morning, becoming sunny in the afternoon. Moderate fog in the morning. Hot. High 92°. Heat index up to 102°. UV index up to 9. Wind south-southwest around 6 mph, gusting to 23 mph, in the morning, becoming 9 mph, gusting to 26 mph, in the afternoon.
Wednesday night	Clear in the evening, becoming mostly clear after midnight. Patchy light fog in the evening, then moderate fog after midnight. Low 73°. Wind south-southwest around 5 mph, gusting to 21 mph.
Thursday	Mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Light to moderate fog in the morning. Very hot. High 94°. Heat index up to 104°. UV index up to 10. Wind south-southwest around 8 mph, gusting to 24 mph.
Thursday night	Fair in the evening, becoming fair to partly cloudy after midnight. Moderate fog after midnight. Low 72°. Wind west-southwest around 4 mph, gusting to 17 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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