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, 06-Sep-2026 05:00 am

Today Mostly Sunny Hot!	Tonight Partly Cloudy	Monday Sunny	Monday night Partly Cloudy	Tuesday Partly Cloudy	Tuesday night Clear	Wednesday Partly Cloudy Hot!	Wednesday night Rain likely
							.75 in.
High: 97°	Low: 71°	High: 92°	Low: 66°	High: 95°	Low: 68°	High: 97°	Low: 71°
Heat: 102°						Heat: 102°
ENE 6-27 mph	ENE 5-23 mph	ENE 5-26 mph	ENE→ESE 4-21 mph	SSE 4-24 mph	SSE 6-18 mph	WSW 6-23 mph	WNW 5-16→calm mph
UV: 8 Very High		UV: 8 Very High		UV: 7 High		UV: 7 High

Today	Sunny in the morning, becoming mostly sunny in the afternoon. Very hot. High 97°. Heat index up to 102°. UV index up to 8. Wind east-northeast around 6 mph, gusting to 27 mph.
Tonight	Fair in the evening, becoming fair to partly cloudy after midnight. Low 71°. Wind east-northeast around 5 mph, gusting to 23 mph.
Monday	Sunny. Very hot. High 92°. UV index up to 8. Wind east-northeast around 5 mph, gusting to 26 mph.
Monday night	Mostly clear in the evening, becoming fair to partly cloudy after midnight. Low 66°. Wind east-northeast around 4 mph, gusting to 21 mph, in the evening, becoming east-southeast after midnight.
Tuesday	Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 95°. UV index up to 7. Wind south-southeast around 4 mph, gusting to 24 mph.
Tuesday night	Fair in the evening, becoming clear after midnight. Low 68°. Wind south-southeast around 6 mph, gusting to 18 mph.
Wednesday	Partly to mostly sunny in the morning, becoming partly cloudy in the afternoon. Very hot. High 97°. Heat index up to 102°. UV index up to 7. Wind west-southwest around 6 mph, gusting to 23 mph.
Wednesday night	Mostly cloudy to cloudy in the evening, becoming dense overcast 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. Precipitation showery or intermittent. Low 71°. Wind west-northwest around 5 mph, gusting to 16 mph, in the evening, becoming near calm after midnight. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch.
Thursday	Mostly cloudy to cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Precipitation showery or intermittent. Warm. High 84°. UV index up to 5. Wind northwest around 4 mph, gusting to 22 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch.
Thursday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Light to moderate fog after midnight. Low 66°. Wind north-northeast around 2 mph, gusting to 18 mph, in the evening, becoming southeast after midnight.
Friday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Light to moderate fog in the morning. Hot. High 86°. UV index up to 7. Wind south around 5 mph, gusting to 21 mph.
Friday night	Mostly clear in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. Low 69°. Wind south-southeast around 6 mph.
Saturday	Partly to mostly sunny in the morning, becoming sunny in the afternoon. Patchy light fog in the morning. Very hot. High 91°. Heat index up to 98°. UV index up to 7. Wind south-southwest around 7 mph, gusting to 22 mph, in the morning, becoming 11 mph, gusting to 24 mph, in the afternoon.
Saturday night	Fair to partly cloudy in the evening, becoming fair after midnight. Warm. Low 73°. Wind south-southwest around 10 mph, gusting to 20 mph.

WXSIM forecast formatting script by Saratoga-Weather.org.

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