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: Tuesday, 16-Jun-2026 04:00 pm

Tonight Fog late	Wednesday Thunder storm	Wednesday night Thunder storm	Thursday Fog a.m.	Thursday night Fog late	Friday Fog a.m.	Friday night Fog late	Saturday Thunder storm
	<.1 in.	<.1 in.	<.1 in.				<.1 in.
Low: 64°	High: 89°	Low: 69°	High: 85°	Low: 65°	High: 85°	Low: 64°	High: 89°
	Heat: 92°
W→S 5-24 mph	SSW 8-24→16-31 mph	WSW 13-27→9-16 mph	NW 6-26 mph	WNW 3-22 mph	NNW 3-22 mph	SSE 4-17 mph	SSE 3-21 mph
	UV: 8 Very High		UV: 8 Very High		UV: 9 Very High		UV: 7 High

Tonight	Fair in the evening, becoming fair to partly cloudy after midnight. Light to moderate fog after midnight. Relatively cool. Low 64°. Wind west around 5 mph, gusting to 24 mph, in the evening, becoming south after midnight.
Wednesday	Partly cloudy. Patchy light fog in the morning. A chance of rain. Scattered thundershowers possible. Breezy and hot. High 89°. Heat index up to 92°. UV index up to 8. Wind south-southwest around 8 mph, gusting to 24 mph, in the morning, becoming 16 mph, gusting to 31 mph, in the afternoon. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Fair to partly cloudy in the evening, becoming fair after midnight. Light to moderate 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 thunderstorms likely. Breezy. Low 69°. Wind west-southwest around 13 mph, gusting to 27 mph, in the evening, becoming 9 mph, gusting to 16 mph, after midnight. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Partly to mostly cloudy. Patchy light fog in the morning. A chance of rain. High 85°. UV index up to 8. Wind northwest around 6 mph, gusting to 26 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 65°. Wind west-northwest around 3 mph, gusting to 22 mph.
Friday	Partly cloudy in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. High 85°. UV index up to 9. Wind north-northwest around 3 mph, gusting to 22 mph.
Friday night	Clear in the evening, becoming mostly clear after midnight. Light to moderate fog after midnight. Relatively cool. Low 64°. Wind south-southeast around 4 mph, gusting to 17 mph.
Saturday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Light to moderate fog in the morning. A slight chance of rain in the afternoon. Scattered thundershowers possible. Hot. High 89°. UV index up to 7. Wind south-southeast around 3 mph, gusting to 21 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Partly to mostly cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog in the evening, then light to moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Scattered thundershowers possible. Low 69°. Wind south-southeast around 5 mph. Chance of precipitation 80 percent. Precipitation mostly around half an inch.
Sunday	Cloudy in the morning, becoming mostly cloudy in the afternoon. Light to moderate fog in the morning, then patchy light fog in the afternoon. Rain likely in the morning, then a chance of rain in the afternoon. Scattered thunderstorms likely. High 84°. UV index up to 6. Wind south-southwest around 7 mph, gusting to 18 mph, in the morning, becoming 10 mph, gusting to 24 mph, in the afternoon. Chance of precipitation 90 percent. Precipitation mostly between half an inch and one inch.
Sunday night	Cloudy. Light to moderate fog. Rain likely in the evening, then a chance of rain after midnight. Scattered thunderstorms likely. Low 71°. Wind west-southwest around 8 mph, gusting to 21 mph. Chance of precipitation 70 percent. Precipitation mostly around a quarter of an inch.
Monday	Mostly cloudy to cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 82°. UV index up to 10. Wind northeast around 9 mph, gusting to 28 mph, in the morning, becoming east in the afternoon.
Monday night	Mostly cloudy. Low 69°. Wind east around 5 mph, gusting to 25 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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