Frost dates for Antelope Ranger Station, SD
At Antelope Ranger Station, the median last spring frost (32°F) is May 19 and the median first fall frost is Sep 19, for a typical growing season of 121 days. For a 90% chance that the last frost has passed, wait until Jun 2. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 19Last spring frost (median)50% chance of 32°F after this date
- Jun 2Safer planting date10% chance of 32°F after this date
- Sep 19First fall frost (median)50% chance of 32°F by this date
- 121 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 31 | Jun 25 |
| 32°F | May 7 | May 19 | Jun 2 |
| 28°F | Apr 28 | May 9 | May 22 |
| 24°F | Apr 15 | Apr 30 | May 13 |
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 24 | Sep 9 | Sep 23 |
| 32°F | Sep 3 | Sep 19 | Oct 2 |
| 28°F | Sep 13 | Sep 28 | Oct 11 |
| 24°F | Sep 19 | Oct 6 | Oct 21 |
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 | 73 days | 99 days | 117 days |
| 32°F | 102 days | 121 days | 138 days |
| 28°F | 120 days | 140 days | 158 days |
| 24°F | 138 days | 157 days | 178 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 |
|---|---|---|---|
| 57720 | 4b | -25 to -20°F | 20 km |
| 57651 | 4b | -25 to -20°F | 24 km |
| 57776 | 4b | -25 to -20°F | 36 km |
| 57755 | 4b | -25 to -20°F | 37 km |
| 57649 | 4b | -25 to -20°F | 38 km |
| 57650 | 4b | -25 to -20°F | 40 km |
| 57724 | 4b | -25 to -20°F | 53 km |
| 57640 | 4b | -25 to -20°F | 55 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 USC00390223, at 45.5317, -103.3292, elevation 860 m (2,820 ft).
- Data quality: Representative (10+ years), 12 years of freeze data.
- Average days per year at or below 32°F: 193.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Buffalo 13 ESE (3 km)
- Redig 11 NE (17 km)
- Buffalo Asos (19 km)
- Ludlow 3 SSE (28 km)
- Ralph 1 N (35 km)
- Hoover (47 km)
- Lodgepole 5sw (48 km)
- Camp Crook (50 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.