Arnold, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Arnold, a city in Jefferson County, Missouri.
This Afternoon
73°F
Rain
Rain and a slight chance of thunderstorms. Cloudy. High near 73, with temperatures falling to around 66 in the afternoon. South wind around 10 mph, with gusts as high as 25 mph. Chance of precipitation is 90%.
7-day forecast for Arnold
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 73°F | Rain | 10 mph S | 85% |
| Tonight | 52°F | Light Rain | 6 to 12 mph SW | 90% |
| Wednesday | 64°F | Mostly Cloudy | 6 to 10 mph W | 4% |
| Wednesday Night | 43°F | Partly Cloudy | 5 mph SW | 0% |
| Thursday | 67°F | Sunny | 3 to 8 mph W | 2% |
| Thursday Night | 43°F | Mostly Cloudy | 5 mph NW | 12% |
| Friday | 59°F | Partly Sunny | 5 to 8 mph NW | 5% |
| Friday Night | 39°F | Mostly Cloudy | 1 to 5 mph N | 2% |
| Saturday | 57°F | Partly Sunny | 3 mph NW | 0% |
| Saturday Night | 36°F | Partly Cloudy | 2 mph NW | 1% |
| Sunday | 63°F | Sunny | 5 mph W | 8% |
| Sunday Night | 36°F | Mostly Clear | 3 mph W | 5% |
| Monday | 67°F | Sunny | 5 mph W | 2% |
| Monday Night | 40°F | Mostly Clear | 3 mph SW | 1% |
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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Herculaneum
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Horine
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Olympian Village
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Peaceful Village
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Raintree Plantation
Scotsdale
Summer Set
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 Nov 4, 2026.