Keystone, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Keystone, a town in Pennington County, South Dakota.
Today
69°F
Areas Of Smoke then Mostly Sunny
Areas of smoke before noon. Mostly sunny, with a high near 69. East wind 1 to 5 mph, with gusts as high as 20 mph.
7-day forecast for Keystone
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 69°F | Areas Of Smoke then Mostly Sunny | 1 to 5 mph E | 8% |
| Tonight | 52°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SW | 18% |
| Wednesday | 79°F | Sunny | 5 mph SW | 7% |
| Wednesday Night | 58°F | Mostly Clear | 5 mph SW | 2% |
| Thursday | 88°F | Sunny | 2 to 6 mph N | 5% |
| Thursday Night | 62°F | Mostly Clear | 5 mph N | 1% |
| Friday | 92°F | Sunny | 3 to 7 mph SE | 2% |
| Friday Night | 67°F | Mostly Clear | 6 mph SW | 1% |
| Saturday | 94°F | Sunny | 7 mph N | 2% |
| Saturday Night | 65°F | Mostly Clear | 2 to 7 mph NW | 2% |
| Sunday | 92°F | Mostly Sunny | 2 to 8 mph SE | 6% |
| Sunday Night | 65°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 to 7 mph N | 15% |
| Monday | 89°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 3 to 8 mph NE | 16% |
| Monday Night | 64°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 1 to 8 mph N | 31% |
Forecast source: National Weather Service (api.weather.gov) for Keystone (43.895, -103.427). Updated through the day.
Growing snapshot for Keystone
Last spring frost
May 15
First fall frost
Oct 1
Growing season
138 days
Hardiness zone
5a
More local growing data for Keystone: nearby ZIP 57751 weather · frost dates · planting calendar · South Dakota frost dates
Nearby towns & communities
Caputa
Colonial Pine Hills
Cottonwood
Green Valley
Hill City
Johnson Siding
New Underwood
Quinn
Rapid City
Wall
Climate data from the nearest NOAA station, Mt Rushmore Nmem, Sd (1.6 mi from Keystone). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.