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, 01-Sep-2026 04:00 pm

Tonight Clear	Wednesday Sunny Hot!	Wednesday night Clear	Thursday Mostly Sunny Hot!	Thursday night Mostly Clear	Friday Mostly Cloudy Hot!	Friday night Partly Cloudy	Saturday Mostly Sunny Hot!
							<.1 in.
Low: 71°	High: 98°	Low: 71°	High: 98°	Low: 72°	High: 98°	Low: 72°	High: 92°
	Heat: 104°		Heat: 105°		Heat: 105°		Heat: 101°
S 4-22 mph	SW 6-23 mph	S 4-16 mph	SW 6-23 mph	SSE 5-16 mph	SW 4-21 mph	SSE 2 mph	NNW 4-16 mph
	UV: 8 Very High		UV: 7 High		UV: 7 High		UV: 8 Very High

Tonight	Clear. Low 71°. Wind south around 4 mph, gusting to 22 mph.
Wednesday	Sunny. Very hot. High 98°. Heat index up to 104°. UV index up to 8. Wind southwest around 6 mph, gusting to 23 mph.
Wednesday night	Fair in the evening, becoming clear after midnight. Low 71°. Wind south around 4 mph, gusting to 16 mph.
Thursday	Sunny in the morning, becoming partly to mostly sunny in the afternoon. Very hot. High 98°. Heat index up to 105°. UV index up to 7. Wind southwest around 6 mph, gusting to 23 mph.
Thursday night	Mostly clear in the evening, becoming clear after midnight. Low 72°. Wind south-southeast around 5 mph, gusting to 16 mph.
Friday	Mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Very hot. High 98°. Heat index up to 105°. UV index up to 7. Wind southwest around 4 mph, gusting to 21 mph.
Friday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 72°. Wind south-southeast around 2 mph.
Saturday	Partly to mostly sunny. A slight chance of rain. Very hot. High 92°. Heat index up to 101°. UV index up to 8. Wind north-northwest around 4 mph, gusting to 16 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Fair to partly cloudy in the evening, becoming mostly clear after midnight. Patchy light fog after midnight. Low 71°. Wind east around 2 mph in the evening, becoming southeast after midnight.
Sunday	Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the afternoon. Hot. High 92°. Heat index up to 98°. UV index up to 6. Wind west-northwest around 3 mph, gusting to 18 mph, in the morning, becoming north in the afternoon. 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. Patchy light fog. A slight chance of rain. Low 70°. Wind east around 3 mph. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.
Monday	Partly to mostly cloudy in the morning, becoming cloudy in the afternoon. Patchy light fog in the morning. Hot. High 86°. UV index up to 5. Wind southwest around 5 mph, gusting to 15 mph, in the morning, becoming west-northwest in the afternoon.
Monday night	Cloudy. Patchy light fog after midnight. A chance of rain. Low 72°. Wind east around 4 mph. 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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