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, 19-Apr-2026 04:00 pm

Tonight Partly Cloudy	Monday Sunny	Monday night Partly Cloudy	Tuesday Partly Cloudy	Tuesday night Partly Cloudy	Wednesday Partly Cloudy	Wednesday night Partly Cloudy	Thursday Mostly Cloudy

Low: 41°	High: 68°	Low: 45°	High: 77°	Low: 49°	High: 76°	Low: 52°	High: 79°

NNE 4-27 mph	E→SE 6-26 mph	SE→SSW 5-21 mph	SSW 8-27→12-30 mph	SW 8-24 mph	SW 7-24 mph	S 5-17 mph	S 9-27→13-29 mph
	UV: 7 High		UV: 7 High		UV: 5 Medium		UV: 6 High

Tonight	Mostly clear in the evening, becoming fair to partly cloudy after midnight. Cool. Low 41°. Wind north-northeast around 4 mph, gusting to 27 mph.
Monday	Sunny. High 68°. UV index up to 7. Wind east around 6 mph, gusting to 26 mph, in the morning, becoming southeast in the afternoon.
Monday night	Mostly clear in the evening, becoming partly cloudy after midnight. Low 45°. Wind southeast around 5 mph, gusting to 21 mph, in the evening, becoming south-southwest after midnight.
Tuesday	Partly cloudy in the morning, becoming sunny in the afternoon. Warm. High 77°. UV index up to 7. Wind south-southwest around 8 mph, gusting to 27 mph, in the morning, becoming 12 mph, gusting to 30 mph, in the afternoon.
Tuesday night	Fair to partly cloudy in the evening, becoming clear after midnight. Low 49°. Wind southwest around 8 mph, gusting to 24 mph.
Wednesday	Partly cloudy. Warm. High 76°. UV index up to 5. Wind southwest around 7 mph, gusting to 24 mph.
Wednesday night	Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Low 52°. Wind south around 5 mph, gusting to 17 mph.
Thursday	Partly to mostly sunny in the morning, becoming partly to mostly cloudy in the afternoon. Warm. High 79°. UV index up to 6. Wind south around 9 mph, gusting to 27 mph, in the morning, becoming 13 mph, gusting to 29 mph, in the afternoon.
Thursday night	Partly to mostly cloudy in the evening, becoming dense overcast after midnight. Patchy light fog after midnight. A chance of rain in the evening, then rain likely after midnight. Scattered thunderstorms likely. Low 58°. Wind south around 9 mph, gusting to 24 mph. Chance of precipitation 80 percent. Precipitation mostly between half an inch and one inch.
Friday	Mostly cloudy to cloudy in the morning, becoming mostly cloudy in the afternoon. Light to moderate fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Scattered thundershowers possible. High 71°. UV index up to 5. Wind south-southwest around 5 mph, gusting to 19 mph, in the morning, becoming west in the afternoon. Chance of precipitation 60 percent. Precipitation mostly around a quarter of an inch.
Friday night	Mostly cloudy to cloudy in the evening, becoming partly cloudy after midnight. Patchy light fog after midnight. A chance of rain. Precipitation showery or intermittent. Low 52°. Wind north-northwest around 6 mph, gusting to 18 mph. Chance of precipitation 50 percent. Precipitation mostly around a tenth of an inch.
Saturday	Partly to mostly cloudy in the morning, becoming dense overcast in the afternoon. Patchy light fog in the morning. A chance of rain in the afternoon. Scattered thundershowers possible. High 69°. UV index up to 6. Wind east-northeast around 7 mph, gusting to 25 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch.
Saturday night	Mostly cloudy to cloudy in the evening, becoming cloudy after midnight. A slight chance of rain. Scattered thundershowers possible. Low 54°. Wind east around 8 mph, gusting to 19 mph, in the evening, becoming 4 mph after midnight. Chance of precipitation 20 percent. Precipitation mostly less than a tenth of an inch.

WXSIM forecast formatting script by Saratoga-Weather.org.

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