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: Saturday, 05-Sep-2026 04:00 pm

Tonight Partly Cloudy	Sunday Mostly Sunny	Sunday night Fog late	Monday Fog a.m.	Monday night Fog late	Tuesday Fog a.m.	Tuesday night Partly Cloudy	Wednesday Partly Cloudy Hot!
							<.1 in.
Low: 74°	High: 92°	Low: 68°	High: 89°	Low: 63°	High: 94°	Low: 69°	High: 95°
	Heat: 99°						Heat: 100°
ENE 4-24 mph	NE 6-26 mph	ENE 6-21 mph	E 6-25 mph	E 4-20 mph	SSE 5-22 mph	SSE 6-17 mph	WSW 6-20 mph
	UV: 7 High		UV: 8 Very High		UV: 7 High		UV: 6 High

Tonight	Fair to partly cloudy in the evening, becoming clear after midnight. Warm. Low 74°. Wind east-northeast around 4 mph, gusting to 24 mph.
Sunday	Partly to mostly sunny. Very hot. High 92°. Heat index up to 99°. UV index up to 7. Wind northeast around 6 mph, gusting to 26 mph.
Sunday night	Fair to partly cloudy. Patchy light fog after midnight. Low 68°. Wind east-northeast around 6 mph, gusting to 21 mph.
Monday	Sunny. Patchy light fog in the morning. Hot. High 89°. UV index up to 8. Wind east around 6 mph, gusting to 25 mph.
Monday night	Fair in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 63°. Wind east around 4 mph, gusting to 20 mph.
Tuesday	Mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. Very hot. High 94°. UV index up to 7. Wind south-southeast around 5 mph, gusting to 22 mph.
Tuesday night	Fair in the evening, becoming fair to partly cloudy after midnight. Low 69°. Wind south-southeast around 6 mph, gusting to 17 mph.
Wednesday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. A chance of rain. Very hot. High 95°. Heat index up to 100°. UV index up to 6. Wind west-southwest around 6 mph, gusting to 20 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Wednesday night	Partly to 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 rain likely after midnight. Precipitation showery or intermittent. Low 70°. Wind northeast around 3 mph in the evening, becoming north around 6 mph after midnight. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Thursday	Cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Light to moderate fog in the morning. Rain likely in the morning, then a slight chance of rain in the afternoon. Precipitation showery or intermittent. Warm. High 84°. UV index up to 6. Wind north-northwest around 3 mph, gusting to 21 mph. Chance of precipitation 70 percent. Precipitation mostly around half an inch.
Thursday night	Fair to partly cloudy in the evening, becoming clear after midnight. Patchy light fog after midnight. Low 66°. Wind east near calm in the evening, becoming south-southeast after midnight.
Friday	Mostly sunny in the morning, becoming partly cloudy in the afternoon. Patchy light fog in the morning. Hot. High 85°. UV index up to 5. Wind south-southeast around 5 mph, gusting to 19 mph.
Friday night	Mostly clear in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. Low 66°. Wind southeast around 5 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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