Castlewood, SD Weather & Growing Conditions
Tonight
38°F
Light Rain
A chance of rain before 7pm, then rain and patchy fog. Cloudy. Low around 38, with temperatures rising to around 41 overnight. North northwest wind 16 to 20 mph, with gusts as high as 37 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 38°F | Light Rain | 16 to 20 mph NNW | 88% |
| Wednesday | 43°F | Light Rain | 20 mph NNW | 88% |
| Wednesday Night | 33°F | Light Rain Likely | 14 to 17 mph NNW | 55% |
| Thursday | 43°F | Patchy Fog then Partly Sunny | 12 to 16 mph N | 4% |
| Thursday Night | 29°F | Mostly Cloudy | 2 to 10 mph NE | 0% |
| Friday | 45°F | Partly Sunny | 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 | 57°F | Sunny | 6 to 10 mph WSW | 3% |
| Sunday Night | 37°F | Mostly Clear | 9 mph SSW | 0% |
| Monday | 58°F | Mostly Sunny | 9 to 15 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). Updated through the day.
Growing snapshot for Castlewood, SD
Last spring frost
May 10
First fall frost
Sep 27
Growing season
139 days
Hardiness zone
4a
Explore more for Castlewood, SD: full frost dates · planting calendar · South Dakota frost dates
Climate data from the nearest NOAA station, Castlewood, Sd (1.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.