Arnold, MO Weather & Growing Conditions
Today
98°F
Mostly Sunny
Mostly sunny, with a high near 98. Heat index values as high as 103. Southwest wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 98°F | Mostly Sunny | 6 mph SW | 1% |
| Tonight | 73°F | Partly Cloudy | 5 mph SW | 5% |
| Sunday | 93°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 5 mph W | 28% |
| Sunday Night | 67°F | Showers And Thunderstorms Likely | 6 mph N | 65% |
| Monday | 79°F | Showers And Thunderstorms Likely | 7 mph N | 66% |
| Monday Night | 59°F | Showers And Thunderstorms Likely | 5 to 8 mph N | 62% |
| Tuesday | 71°F | Slight Chance Rain Showers then Partly Sunny | 8 mph N | 22% |
| Tuesday Night | 54°F | Mostly Cloudy | 5 to 8 mph N | 4% |
| Wednesday | 74°F | Mostly Sunny | 7 mph N | 1% |
| Wednesday Night | 55°F | Partly Cloudy | 2 to 6 mph N | 1% |
| Thursday | 76°F | Mostly Sunny | 2 to 6 mph N | 2% |
| Thursday Night | 57°F | Mostly Cloudy | 5 mph NE | 4% |
| Friday | 77°F | Partly Sunny | 2 to 6 mph NE | 8% |
| Friday Night | 57°F | Partly Cloudy | 5 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Arnold, MO
Last spring frost
Apr 9
First fall frost
Oct 26
Growing season
197 days
Hardiness zone
7a
Explore more for Arnold, MO: full frost dates · planting calendar · Missouri frost dates
Climate data from the nearest NOAA station, Festus, Mo (11.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.