Keystone, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Keystone, a town in Pennington County, South Dakota.
This Afternoon
55°F
Sunny
Sunny. High near 55, with temperatures falling to around 43 in the afternoon. Northwest wind around 6 mph, with gusts as high as 22 mph.
7-day forecast for Keystone
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 55°F | Sunny | 6 mph NW | 0% |
| Tonight | 33°F | Mostly Clear | 6 mph NW | 0% |
| Wednesday | 53°F | Partly Sunny | 6 mph N | 1% |
| Wednesday Night | 34°F | Mostly Cloudy | 2 to 7 mph NW | 1% |
| Thursday | 58°F | Sunny | 3 mph S | 0% |
| Thursday Night | 37°F | Partly Cloudy | 5 mph W | 0% |
| Friday | 56°F | Mostly Sunny | 0 to 5 mph N | 2% |
| Friday Night | 36°F | Mostly Clear | 2 to 6 mph W | 3% |
| Saturday | 59°F | Sunny | 2 to 6 mph NW | 3% |
| Saturday Night | 38°F | Mostly Clear | 6 mph W | 1% |
| Sunday | 67°F | Sunny | 7 mph W | 0% |
| Sunday Night | 45°F | Mostly Clear | 6 to 10 mph W | 0% |
| Monday | 61°F | Sunny | 2 to 6 mph N | 0% |
| Monday Night | 41°F | Partly Cloudy | 5 mph W | 0% |
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 Nov 4, 2026.