Castlewood, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Castlewood, a city in Hamlin County, South Dakota.
Tonight
38°F
Light Rain
Rain and patchy fog. Cloudy. Low around 38, with temperatures rising to around 41 overnight. North northwest wind 15 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Castlewood
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 38°F | Light Rain | 15 to 21 mph NNW | 88% |
| Wednesday | 43°F | Light Rain | 20 mph NNW | 88% |
| Wednesday Night | 33°F | Chance Light Rain | 14 to 17 mph NNW | 53% |
| Thursday | 43°F | Patchy Fog then Partly Sunny | 12 to 15 mph N | 4% |
| Thursday Night | 28°F | Mostly Cloudy | 1 to 10 mph NE | 0% |
| Friday | 45°F | Partly Sunny | 1 to 5 mph SE | 0% |
| Friday Night | 29°F | Partly Cloudy | 5 mph SSW | 0% |
| Saturday | 54°F | Mostly Sunny | 5 to 13 mph WSW | 3% |
| Saturday Night | 33°F | Partly Cloudy | 6 to 9 mph W | 4% |
| Sunday | 56°F | Sunny | 6 to 10 mph WSW | 3% |
| Sunday Night | 37°F | Mostly Clear | 8 mph SSW | 0% |
| Monday | 58°F | Mostly Sunny | 8 to 16 mph W | 0% |
| Monday Night | 35°F | Mostly Clear | 5 to 9 mph WNW | 0% |
| Tuesday | 55°F | Mostly Sunny | 5 to 9 mph W | 0% |
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 Nov 4, 2026.