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: Sunday, 07-Jun-2026 05:00 am

Today Thunder storm	Tonight Thunder storm	Monday Thunder storm	Monday night Thunder storm	Tuesday Thunder storm Hot!	Tuesday night Fog late	Wednesday Fog a.m. Hot!	Wednesday night Fog late
<.1 in.	<.25 in.	.25 in.	.35 in.	<.1 in.
High: 89°	Low: 76°	High: 84°	Low: 74°	High: 91°	Low: 74°	High: 93°	Low: 75°
Heat: 94°				Heat: 101°		Heat: 103°
SE 4-24→9-26 mph	SE 8-24 mph	S 7-25 mph	SSW 5-21 mph	SSW 4-23→7-25 mph	SSW 5-20 mph	SSW 10-28 mph	SSW 8-23 mph
UV: 8 Very High		UV: 5 Medium		UV: 9 Very High		UV: 8 Very High

Today	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. A chance of rain. Scattered thundershowers possible. Hot. High 89°. Heat index up to 94°. UV index up to 8. Wind southeast around 4 mph, gusting to 24 mph, in the morning, becoming 9 mph, gusting to 26 mph, in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tonight	Cloudy in the evening, becoming dense overcast after midnight. Patchy light fog after midnight. Rain likely. Scattered thunderstorms likely. Warm. Low 76°. Wind southeast around 8 mph, gusting to 24 mph. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch.
Monday	Mostly cloudy. Patchy light fog in the morning. Rain likely. Scattered thunderstorms likely. High 84°. UV index up to 5. Wind south around 7 mph, gusting to 25 mph. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch.
Monday night	Mostly cloudy. Light to moderate fog in the evening, then moderate fog after midnight. Rain likely. Scattered thundershowers possible. Low 74°. Wind south-southwest around 5 mph, gusting to 21 mph. Chance of precipitation 70 percent. Precipitation mostly between a quarter and half an inch.
Tuesday	Partly to mostly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Moderate fog in the morning. A slight chance of rain. Scattered thundershowers possible. Hot. High 91°. Heat index up to 101°. UV index up to 9. Wind south-southwest around 4 mph, gusting to 23 mph, in the morning, becoming 7 mph, gusting to 25 mph, in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Fair in the evening, becoming clear after midnight. Patchy light fog in the evening, then moderate fog after midnight. Low 74°. Wind south-southwest around 5 mph, gusting to 20 mph.
Wednesday	Sunny in the morning, becoming partly cloudy in the afternoon. Moderate fog in the morning. Hot. High 93°. Heat index up to 103°. UV index up to 8. Wind south-southwest around 10 mph, gusting to 28 mph.
Wednesday night	Mostly clear in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. Low 75°. Wind south-southwest around 8 mph, gusting to 23 mph.
Thursday	Sunny in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 95°. Heat index up to 105°. UV index up to 9. Wind south-southwest around 10 mph, gusting to 29 mph.
Thursday night	Partly to mostly cloudy in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. A chance of rain. Scattered thunderstorms likely. Low 72°. Wind south-southwest around 7 mph, gusting to 25 mph, in the evening, becoming northwest after midnight. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Friday	Sunny. Patchy light fog in the morning. Hot. High 87°. Heat index up to 92°. UV index up to 9. Wind northwest around 5 mph, gusting to 24 mph.
Friday night	Clear in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 67°. Wind east-northeast around 3 mph, gusting to 19 mph, in the evening, becoming southeast after midnight.
Saturday	Mostly cloudy. Patchy light fog in the morning. Rain likely. Scattered thundershowers possible. High 81°. UV index up to 5. Wind south-southeast around 2 mph, gusting to 15 mph. Chance of precipitation 60 percent. Precipitation mostly between a quarter and half an inch.
Saturday night	Partly to mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Light to moderate fog in the evening, then moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Scattered thundershowers possible. Low 69°. Wind south around 5 mph in the evening, becoming northwest after midnight. Chance of precipitation 70 percent. Precipitation mostly around half an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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