National Weather Service Forecast for: Arnold MO
Issued by: National Weather Service Saint Louis, MO
Updated: 3:31 pm CDT Mar 19, 2026
 
Tonight

Tonight: Mostly clear, with a low around 52. South wind 3 to 5 mph.
Mostly Clear
 Friday

Friday: Sunny, with a high near 83. Light southwest wind becoming west 6 to 11 mph in the morning. Winds could gust as high as 20 mph.
Sunny
 Friday
Night
Friday Night: Partly cloudy, with a low around 52. Light north wind.
Partly Cloudy
 Saturday

Saturday: Sunny, with a high near 82. Light and variable wind.
Sunny
 Saturday
Night
Saturday Night: Clear, with a low around 60. Calm wind becoming south 5 to 7 mph in the evening.
Clear
 Sunday

Sunday: Sunny, with a high near 87.
Sunny
 Sunday
Night
Sunday Night: Partly cloudy, with a low around 42.
Partly Cloudy
 Monday

Monday: Mostly sunny, with a high near 59.
Mostly Sunny
 Monday
Night
Monday Night: Partly cloudy, with a low around 39.
Partly Cloudy
Lo 52 °F Hi 83 °F Lo 52 °F Hi 82 °F Lo 60 °F Hi 87 °F Lo 42 °F Hi 59 °F Lo 39 °F

 

Tonight
 
 Mostly clear, with a low around 52. South wind 3 to 5 mph.
Friday
 
 Sunny, with a high near 83. Light southwest wind becoming west 6 to 11 mph in the morning. Winds could gust as high as 20 mph.
Friday Night
 
 Partly cloudy, with a low around 52. Light north wind.
Saturday
 
 Sunny, with a high near 82. Light and variable wind.
Saturday Night
 
 Clear, with a low around 60. Calm wind becoming south 5 to 7 mph in the evening.
Sunday
 
 Sunny, with a high near 87.
Sunday Night
 
 Partly cloudy, with a low around 42.
Monday
 
 Mostly sunny, with a high near 59.
Monday Night
 
 Partly cloudy, with a low around 39.
Tuesday
 
 Partly sunny, with a high near 63.
Tuesday Night
 
 Mostly cloudy, with a low around 44.
Wednesday
 
 Mostly sunny, with a high near 72.
Wednesday Night
 
 Mostly clear, with a low around 55.
Thursday
 
 A 20 percent chance of rain. Mostly sunny, with a high near 79.

 

Forecast from NOAA-NWS for Arnold MO.