Castlewood, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Castlewood, a city in Hamlin County, South Dakota.
Today
71°F
Mostly Sunny
Mostly sunny, with a high near 71. Northwest wind around 10 mph.
7-day forecast for Castlewood
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 71°F | Mostly Sunny | 10 mph NW | 2% |
| Tonight | 52°F | Mostly Clear | 2 to 7 mph SW | 0% |
| Wednesday | 77°F | Sunny | 5 to 13 mph SSW | 0% |
| Wednesday Night | 58°F | Mostly Clear | 7 to 10 mph SSW | 1% |
| Thursday | 82°F | Sunny | 10 to 16 mph SSW | 3% |
| Thursday Night | 61°F | Mostly Clear | 10 mph SSW | 4% |
| Friday | 85°F | Sunny | 12 mph SSW | 11% |
| Friday Night | 61°F | Mostly Clear | 5 to 8 mph SSE | 11% |
| Saturday | 85°F | Sunny | 6 to 15 mph SSE | 6% |
| Saturday Night | 63°F | Slight Chance Showers And Thunderstorms | 10 to 14 mph ESE | 21% |
| Sunday | 83°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 13 mph E | 19% |
| Sunday Night | 63°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 10 mph E | 22% |
| Monday | 82°F | Slight Chance Showers And Thunderstorms then Partly Sunny | 10 to 15 mph ENE | 22% |
| Monday Night | 62°F | Slight Chance Showers And Thunderstorms | 9 to 15 mph ENE | 15% |
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 Aug 4, 2026.