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, 08-Sep-2026 05:00 am

Today Partly Cloudy	Tonight Mostly Clear	Wednesday Thunder storm	Wednesday night Rain likely	Thursday Rain likely	Thursday night Fog	Friday Fog a.m.	Friday night Fog late
		<.1 in.	.5 in.	.25 in.
High: 92°	Low: 65°	High: 98°	Low: 70°	High: 80°	Low: 67°	High: 85°	Low: 68°

SSE 4-21 mph	SSE 5 mph	WSW 7-23 mph	ESE→NW 3 mph	WNW 4-19 mph	N 3-16 mph	ENE→SE 4-21 mph	ESE→SSE 5-16 mph
UV: 6 High		UV: 7 High		UV: 4 Medium		UV: 6 High

Today	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 92°. UV index up to 6. Wind south-southeast around 4 mph, gusting to 21 mph.
Tonight	Fair in the evening, becoming mostly clear after midnight. Low 65°. Wind south-southeast around 5 mph.
Wednesday	Partly cloudy. A chance of rain. Scattered thundershowers possible. Extremely hot. High 98°. UV index up to 7. Wind west-southwest around 7 mph, gusting to 23 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Mostly cloudy. Moderate fog after midnight. A chance of rain in the evening, then rain likely after midnight. Precipitation showery or intermittent. Low 70°. Wind east-southeast around 3 mph in the evening, becoming northwest after midnight. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Thursday	Partly to mostly cloudy in the morning, becoming mostly cloudy in the afternoon. Moderate fog in the morning. Rain likely. High 80°. UV index up to 4. Wind west-northwest around 4 mph, gusting to 19 mph. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch.
Thursday night	Partly cloudy. Patchy light fog. Low 67°. Wind north around 3 mph, gusting to 16 mph.
Friday	Partly to mostly cloudy in the morning, becoming mostly sunny in the afternoon. Patchy light fog in the morning. Warm. High 85°. UV index up to 6. Wind east-northeast around 4 mph, gusting to 21 mph, in the morning, becoming southeast in the afternoon.
Friday night	Clear in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 68°. Wind east-southeast around 5 mph, gusting to 16 mph, in the evening, becoming south-southeast after midnight.
Saturday	Partly to mostly cloudy. Patchy light fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Hot. High 87°. Heat index up to 93°. UV index up to 6. Wind south-southwest around 5 mph, gusting to 19 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Partly cloudy. Patchy light fog after midnight. Low 68°. Wind west around 2 mph in the evening, becoming north-northwest after midnight.
Sunday	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. Patchy light fog in the morning. Hot. High 86°. UV index up to 5. Wind northeast around 4 mph, gusting to 18 mph, in the morning, becoming south-southwest in the afternoon.
Sunday night	Partly cloudy. Patchy light fog. A chance of rain. Scattered thundershowers possible. Low 67°. Wind south-southwest around 3 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Monday	Partly to mostly cloudy in the morning, becoming sunny in the afternoon. Very hot. High 94°. Heat index up to 102°. UV index up to 7. Wind southwest around 7 mph, gusting to 20 mph, in the morning, becoming 11 mph, gusting to 23 mph, in the afternoon.
Monday night	Mostly clear in the evening, becoming fair after midnight. Patchy light fog after midnight. Warm. Low 72°. Wind southwest around 5 mph, gusting to 15 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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