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, 11-Sep-2026 04:00 pm

Tonight Fog late	Saturday Fog a.m.	Saturday night Mostly Cloudy	Sunday Partly Cloudy	Sunday night Partly Cloudy	Monday Partly Cloudy	Monday night Fog late	Tuesday Thunder storm
			<.1 in.		<.1 in.		<.1 in.
Low: 68°	High: 89°	Low: 65°	High: 87°	Low: 61°	High: 84°	Low: 60°	High: 96°
	Heat: 93°
SSE 3-20 mph	WSW 4-22 mph	NNW 2 mph	NNE 4-21 mph	NNE 7-16 mph	ESE 7-21 mph	SE 7-18 mph	S→SW 6-22 mph
	UV: 6 High		UV: 5 Medium		UV: 6 High		UV: 6 High

Tonight	Partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog in the evening, then moderate fog after midnight. Low 68°. Wind south-southeast around 3 mph, gusting to 20 mph.
Saturday	Sunny in the morning, becoming mostly sunny in the afternoon. Light to moderate fog in the morning. Hot. High 89°. Heat index up to 93°. UV index up to 6. Wind west-southwest around 4 mph, gusting to 22 mph.
Saturday night	Fair in the evening, becoming partly to mostly cloudy after midnight. Low 65°. Wind north-northwest around 2 mph.
Sunday	Partly to mostly cloudy in the morning, becoming partly cloudy in the afternoon. A chance of rain in the afternoon. Hot. High 87°. UV index up to 5. Wind north-northeast around 4 mph, gusting to 21 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Sunday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Low 61°. Wind north-northeast around 7 mph, gusting to 16 mph.
Monday	Mostly cloudy in the morning, becoming partly cloudy in the afternoon. A slight chance of rain. Warm. High 84°. UV index up to 6. Wind east-southeast around 7 mph, gusting to 21 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday night	Clear. Patchy light fog after midnight. Low 60°. Wind southeast around 7 mph, gusting to 18 mph.
Tuesday	Sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the afternoon. Scattered thundershowers possible. Very hot. High 96°. UV index up to 6. Wind south around 6 mph, gusting to 22 mph, in the morning, becoming southwest in the afternoon. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Tuesday night	Partly cloudy in the evening, becoming fair after midnight. Low 65°. Wind northeast around 2 mph in the evening, becoming southeast after midnight.
Wednesday	Sunny in the morning, becoming partly cloudy in the afternoon. Very hot. High 96°. Heat index up to 101°. UV index up to 6. Wind southwest around 2 mph, gusting to 17 mph, in the morning, becoming 6 mph, gusting to 23 mph, in the afternoon.
Wednesday night	Fair to partly cloudy in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain. Precipitation showery or intermittent. Low 65°. Wind north-northeast around 4 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Thursday	Partly cloudy. Light to moderate fog in the morning. A chance of rain. Precipitation showery or intermittent. Hot. High 86°. UV index up to 5. Wind north around 5 mph, gusting to 17 mph, in the morning, becoming northeast in the afternoon. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Fair to partly cloudy in the evening, becoming cloudy after midnight. Patchy light fog after midnight. A chance of rain. Low 63°. Wind northeast around 7 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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