Frost dates for Hill City, SD
At Hill City, the median last spring frost (32°F) is Jun 1 and the median first fall frost is Sep 10, for a typical growing season of 102 days. For a 90% chance that the last frost has passed, wait until Jun 19. Nearby ZIP codes are in USDA hardiness zones 4b to 5b.
- Jun 1Last spring frost (median)50% chance of 32°F after this date
- Jun 19Safer planting date10% chance of 32°F after this date
- Sep 10First fall frost (median)50% chance of 32°F by this date
- 102 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | May 31 | Jun 18 | Jul 7 |
| 32°F | May 18 | Jun 1 | Jun 19 |
| 28°F | May 6 | May 18 | Jun 1 |
| 24°F | Apr 24 | May 6 | May 19 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Aug 12 | Sep 1 | Sep 14 |
| 32°F | Aug 29 | Sep 10 | Sep 26 |
| 28°F | Sep 6 | Sep 21 | Oct 6 |
| 24°F | Sep 16 | Oct 1 | Oct 16 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 46 days | 73 days | 94 days |
| 32°F | 76 days | 102 days | 121 days |
| 28°F | 105 days | 126 days | 146 days |
| 24°F | 127 days | 148 days | 168 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 57751 | 5a | -20 to -15°F | 13 km |
| 57702 | 5a | -20 to -15°F | 16 km |
| 57745 | 4b | -25 to -20°F | 20 km |
| 57730 | 5a | -20 to -15°F | 24 km |
| 57718 | 5a | -20 to -15°F | 30 km |
| 57759 | 5a | -20 to -15°F | 33 km |
| 57701 | 5b | -15 to -10°F | 35 km |
| 57773 | 5b | -15 to -10°F | 38 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00393868, at 43.9342, -103.5572, elevation 1508 m (4,946 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 212.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mount Rushmore Nmem (10 km)
- Pactola Dam (15 km)
- Custer (18 km)
- Johnson Siding (19 km)
- Custer Co Airport (23 km)
- Rochford 2 WNW (27 km)
- Rapid City 4nw (30 km)
- Rapid City WFO (32 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.