Frost dates for De Smet, SD
At De Smet, the median last spring frost (32°F) is May 5 and the median first fall frost is Oct 4, for a typical growing season of 151 days. For a 90% chance that the last frost has passed, wait until May 20. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 5Last spring frost (median)50% chance of 32°F after this date
- May 20Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 151 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 3 | May 16 | May 30 |
| 32°F | Apr 22 | May 5 | May 20 |
| 28°F | Apr 11 | Apr 28 | May 10 |
| 24°F | Apr 2 | Apr 15 | May 2 |
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 15 | Sep 26 | Oct 8 |
| 32°F | Sep 23 | Oct 4 | Oct 17 |
| 28°F | Sep 30 | Oct 14 | Oct 27 |
| 24°F | Oct 8 | Oct 23 | Nov 5 |
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 | 114 days | 133 days | 150 days |
| 32°F | 131 days | 151 days | 170 days |
| 28°F | 149 days | 169 days | 189 days |
| 24°F | 167 days | 188 days | 208 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 57231 | 4b | -25 to -20°F | 3 km |
| 57249 | 4b | -25 to -20°F | 14 km |
| 57233 | 4b | -25 to -20°F | 19 km |
| 57353 | 4b | -25 to -20°F | 23 km |
| 57221 | 4b | -25 to -20°F | 27 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 USC00392302, at 44.3825, -97.5497, elevation 520 m (1,705 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 165.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Arlington 1 W (30 km)
- Howard (41 km)
- Winfred 2s (48 km)
- Huron Regional Airport (54 km)
- Forestburg 4 NNE (55 km)
- Castlewood #2 (56 km)
- Castlewood (56 km)
- Madison 2se (57 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.