Frost dates for Edgemont 23 NNW, SD
At Edgemont 23 NNW, the median last spring frost (32°F) is May 18 and the median first fall frost is Sep 27, for a typical growing season of 130 days. For a 90% chance that the last frost has passed, wait until Jun 1. Nearby ZIP codes are in USDA hardiness zones 4b to 5b.
- May 18Last spring frost (median)50% chance of 32°F after this date
- Jun 1Safer planting date10% chance of 32°F after this date
- Sep 27First fall frost (median)50% chance of 32°F by this date
- 130 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 17 | May 29 | Jun 15 |
| 32°F | May 4 | May 18 | Jun 1 |
| 28°F | Apr 25 | May 7 | May 20 |
| 24°F | Apr 12 | Apr 26 | May 9 |
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 | Sep 5 | Sep 19 | Oct 1 |
| 32°F | Sep 14 | Sep 27 | Oct 10 |
| 28°F | Sep 22 | Oct 5 | Oct 19 |
| 24°F | Oct 1 | Oct 15 | Oct 28 |
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 | 91 days | 111 days | 130 days |
| 32°F | 110 days | 130 days | 150 days |
| 28°F | 131 days | 151 days | 170 days |
| 24°F | 152 days | 172 days | 191 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 |
|---|---|---|---|
| 57730 | 5a | -20 to -15°F | 24 km |
| 57773 | 5b | -15 to -10°F | 26 km |
| 57735 | 4b | -25 to -20°F | 38 km |
| 57747 | 5a | -20 to -15°F | 43 km |
| 82701 | 4b | -25 to -20°F | 44 km |
| 57745 | 4b | -25 to -20°F | 45 km |
| 57751 | 5a | -20 to -15°F | 48 km |
| 82723 | 4b | -25 to -20°F | 58 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 USC00392565, at 43.6242, -103.9172, elevation 1342 m (4,402 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 185.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Custer Co Airport (27 km)
- Custer (30 km)
- Edgemont (35 km)
- Wind Cave (36 km)
- Hot Springs (41 km)
- Hill City (45 km)
- Mount Rushmore Nmem (46 km)
- Oral (58 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.