Castlewood, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Castlewood, a city in Hamlin County, South Dakota.
Overnight
57°F
Areas Of Fog
Areas of fog and a slight chance of drizzle. Cloudy, with a low around 57. Northeast wind around 7 mph.
7-day forecast for Castlewood
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 57°F | Areas Of Fog | 7 mph NE | 10% |
| Saturday | 63°F | Areas Of Fog | 8 to 13 mph NE | 16% |
| Saturday Night | 50°F | Patchy Fog then Mostly Cloudy | 7 to 13 mph NE | 8% |
| Sunday | 64°F | Mostly Cloudy | 12 to 15 mph NE | 13% |
| Sunday Night | 49°F | Chance Rain Showers | 9 to 13 mph ENE | 44% |
| Monday | 62°F | Chance Rain Showers | 12 mph E | 44% |
| Monday Night | 45°F | Mostly Cloudy | 5 to 9 mph E | 6% |
| Tuesday | 65°F | Partly Sunny | 5 to 12 mph SE | 2% |
| Tuesday Night | 47°F | Partly Cloudy | 9 mph SE | 4% |
| Wednesday | 67°F | Partly Sunny | 9 to 15 mph SSE | 10% |
| Wednesday Night | 51°F | Chance Rain Showers | 10 mph SSE | 30% |
| Thursday | 70°F | Chance Rain Showers | 10 mph SSE | 30% |
| Thursday Night | 52°F | Mostly Cloudy | 7 mph SSE | 10% |
| Friday | 71°F | Partly Sunny | 6 to 13 mph SE | 11% |
Forecast source: National Weather Service (api.weather.gov) for Castlewood (44.724, -97.031). Updated through the day.
Growing snapshot for Castlewood
Last spring frost
May 10
First fall frost
Sep 27
Growing season
139 days
Hardiness zone
4a
More local growing data for Castlewood: nearby ZIP 57223 weather · frost dates · planting calendar · South Dakota frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Castlewood, Sd (1.9 mi from Castlewood). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.