Frost dates for Ardmore 1 NW, SD
At Ardmore 1 NW, the median last spring frost (32°F) is May 16 and the median first fall frost is Sep 23, for a typical growing season of 128 days. For a 90% chance that the last frost has passed, wait until May 31. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 16Last spring frost (median)50% chance of 32°F after this date
- May 31Safer planting date10% chance of 32°F after this date
- Sep 23First fall frost (median)50% chance of 32°F by this date
- 128 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 16 | May 29 | Jun 12 |
| 32°F | May 3 | May 16 | May 31 |
| 28°F | Apr 24 | May 6 | May 19 |
| 24°F | Apr 12 | Apr 27 | May 8 |
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 31 | Sep 13 | Sep 27 |
| 32°F | Sep 9 | Sep 23 | Oct 6 |
| 28°F | Sep 18 | Oct 2 | Oct 14 |
| 24°F | Sep 27 | Oct 11 | Oct 23 |
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 | 85 days | 106 days | 126 days |
| 32°F | 107 days | 128 days | 147 days |
| 28°F | 129 days | 147 days | 165 days |
| 24°F | 148 days | 167 days | 187 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 |
|---|---|---|---|
| 57735 | 4b | -25 to -20°F | 33 km |
| 57763 | 5a | -20 to -15°F | 35 km |
| 69367 | 5a | -20 to -15°F | 37 km |
| 57747 | 5a | -20 to -15°F | 40 km |
| 57782 | 5a | -20 to -15°F | 46 km |
| 69346 | 5a | -20 to -15°F | 46 km |
| 69339 | 5a | -20 to -15°F | 53 km |
| 57766 | 5a | -20 to -15°F | 53 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 USC00390236, at 43.0300, -103.6600, elevation 1079 m (3,540 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 191.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Edgemont (34 km)
- Oelrichs (39 km)
- Hot Springs (48 km)
- Oral (52 km)
- Wind Cave (60 km)
- Edgemont 23 NNW (69 km)
- Oglala 1s (76 km)
- Custer Co Airport (78 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.