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, 17-May-2026 04:00 pm

Tonight Thunder storm	Monday Thunder storm	Monday night Thunder storm	Tuesday Thunder storm	Tuesday night Thunder storm	Wednesday Fog a.m.	Wednesday night Mostly Cloudy	Thursday Partly Cloudy
<.1 in.	.5 in.	<.1 in.	<.25 in.	<.1 in.
Low: 69°	High: 82°	Low: 71°	High: 77°	Low: 59°	High: 74°	Low: 53°	High: 72°

S 9-26 mph	S 10-26 mph	S 13-23 mph	SSW→W 11-25 mph	NW 7-20 mph	N 8-27 mph	NNE→ENE 6-24 mph	ENE 7-25 mph
	UV: 9 Very High		UV: 5 Medium		UV: 8 Very High		UV: 6 High

Tonight	Fair to partly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Patchy light fog after midnight. A chance of rain. Scattered thundershowers possible. Low 69°. Wind south around 9 mph, gusting to 26 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Monday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog. A chance of rain in the morning, then rain likely in the afternoon. Scattered thunderstorms likely. High 82°. UV index up to 9. Wind south around 10 mph, gusting to 26 mph. Chance of precipitation 80 percent. Precipitation mostly around half an inch.
Monday night	Partly cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog. A chance of rain. Scattered thundershowers possible. Breezy and warm. Low 71°. Wind south around 13 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Tuesday	Mostly cloudy to cloudy in the morning, becoming cloudy in the afternoon. Patchy light fog in the morning. Rain likely. Thunderstorms very likely, some severe. High 77°. UV index up to 5. Wind south-southwest around 11 mph, gusting to 25 mph, in the morning, becoming west in the afternoon. Chance of precipitation 60 percent. Precipitation mostly less than a quarter of an inch.
Tuesday night	Cloudy in the evening, becoming mostly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain. Scattered thundershowers possible. Low 59°. Wind northwest around 7 mph, gusting to 20 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Wednesday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. High 74°. UV index up to 8. Wind north around 8 mph, gusting to 27 mph.
Wednesday night	Partly to mostly cloudy. Cool. Low 53°. Wind north-northeast around 6 mph, gusting to 24 mph, in the evening, becoming east-northeast after midnight.
Thursday	Partly cloudy in the morning, becoming mostly cloudy to cloudy in the afternoon. High 72°. UV index up to 6. Wind east-northeast around 7 mph, gusting to 25 mph.
Thursday night	Mostly cloudy to cloudy. Relatively cool. Low 54°. Wind east-southeast around 7 mph, gusting to 21 mph.
Friday	Mostly cloudy to cloudy. A slight chance of rain. Precipitation showery or intermittent. High 77°. UV index up to 6. Wind east-southeast around 6 mph, gusting to 23 mph, in the morning, becoming south-southeast in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Friday night	Mostly cloudy in the evening, becoming mostly cloudy to cloudy after midnight. Light to moderate fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Precipitation showery or intermittent. Low 59°. Wind southwest around 5 mph, gusting to 17 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
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 morning, then a chance of rain in the afternoon. Scattered thunderstorms likely. High 79°. UV index up to 7. Wind west-southwest around 9 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Fair to partly cloudy in the evening, becoming cloudy after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Scattered thunderstorms likely. Low 61°. Wind west-northwest around 5 mph, gusting to 19 mph, in the evening, becoming east-southeast around 2 mph after midnight. 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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