Keystone, SD Weather & Growing Conditions
Overnight
47°F
Areas Of Smoke
Areas of smoke. Mostly clear. Low around 47, with temperatures rising to around 51 overnight. Northwest wind around 1 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 47°F | Areas Of Smoke | 1 mph NW | 1% |
| Tuesday | 68°F | Areas Of Smoke then Mostly Sunny | 1 to 5 mph NE | 8% |
| Tuesday Night | 52°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SW | 18% |
| Wednesday | 77°F | Sunny | 5 mph SW | 7% |
| Wednesday Night | 58°F | Mostly Clear | 5 mph SW | 1% |
| Thursday | 86°F | Sunny | 5 mph N | 5% |
| Thursday Night | 63°F | Mostly Clear | 5 mph N | 1% |
| Friday | 90°F | Sunny | 3 to 7 mph SE | 2% |
| Friday Night | 67°F | Mostly Clear | 3 to 7 mph SW | 1% |
| Saturday | 93°F | Sunny | 7 mph N | 2% |
| Saturday Night | 65°F | Mostly Clear | 2 to 7 mph N | 2% |
| Sunday | 91°F | Mostly Sunny | 2 to 8 mph SE | 6% |
| Sunday Night | 66°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 to 7 mph N | 15% |
| Monday | 88°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 3 to 8 mph N | 16% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Keystone, SD
Last spring frost
May 15
First fall frost
Oct 1
Growing season
138 days
Hardiness zone
5a
Explore more for Keystone, SD: full frost dates · planting calendar · South Dakota frost dates
Climate data from the nearest NOAA station, Mt Rushmore Nmem, Sd (1.6 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.