Harman US

Arnold, MO Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Arnold, a city in Jefferson County, Missouri.

Overnight
73°F
Mostly Clear
Mostly clear, with a low around 73. Southeast wind around 3 mph.

7-day forecast for Arnold

WhenTempForecastWindPrecip
Overnight 73°F Mostly Clear 3 mph SE 3%
Saturday 99°F Mostly Sunny 2 to 6 mph SW 4%
Saturday Night 73°F Partly Cloudy 5 mph SW 4%
Sunday 94°F Partly Sunny then Slight Chance Showers And Thunderstorms 5 mph W 28%
Sunday Night 67°F Slight Chance Showers And Thunderstorms then Showers And Thunderstorms Likely 3 to 7 mph N 65%
Monday 80°F Showers And Thunderstorms Likely 7 mph N 65%
Monday Night 59°F Showers And Thunderstorms Likely 5 to 8 mph N 61%
Tuesday 72°F Slight Chance Rain Showers then Partly Sunny 9 mph N 22%
Tuesday Night 54°F Mostly Cloudy 3 to 9 mph N 4%
Wednesday 74°F Mostly Sunny 7 mph N 1%
Wednesday Night 55°F Partly Cloudy 2 to 6 mph N 0%
Thursday 77°F Mostly Sunny 2 to 6 mph N 1%
Thursday Night 57°F Mostly Cloudy 5 mph NE 4%
Friday 77°F Partly Sunny 2 to 6 mph NE 7%

Forecast source: National Weather Service (api.weather.gov) for Arnold (38.426, -90.369). Updated through the day.

Growing snapshot for Arnold

Last spring frost
Apr 9
First fall frost
Oct 26
Growing season
197 days
Hardiness zone
7a

More local growing data for Arnold: nearby ZIP 63010 weather · frost dates · planting calendar · Missouri frost dates

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Climate data from the nearest NOAA station, Festus, Mo (13.7 mi from Arnold). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.