Frost dates for Summit 1 W, SD
At Summit 1 W, the median last spring frost (32°F) is May 14 and the median first fall frost is Sep 28, for a typical growing season of 136 days. For a 90% chance that the last frost has passed, wait until May 28. Nearby ZIP codes are in USDA hardiness zones 4a to 4b.
- May 14Last spring frost (median)50% chance of 32°F after this date
- May 28Safer planting date10% chance of 32°F after this date
- Sep 28First fall frost (median)50% chance of 32°F by this date
- 136 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 12 | May 24 | Jun 7 |
| 32°F | May 1 | May 14 | May 28 |
| 28°F | Apr 21 | May 4 | May 17 |
| 24°F | Apr 11 | Apr 24 | May 7 |
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 4 | Sep 18 | Oct 1 |
| 32°F | Sep 13 | Sep 28 | Oct 10 |
| 28°F | Sep 24 | Oct 4 | Oct 19 |
| 24°F | Sep 30 | Oct 13 | Oct 27 |
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 | 98 days | 117 days | 136 days |
| 32°F | 116 days | 136 days | 153 days |
| 28°F | 134 days | 153 days | 171 days |
| 24°F | 152 days | 172 days | 193 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 |
|---|---|---|---|
| 57266 | 4a | -30 to -25°F | 3 km |
| 57251 | 4b | -25 to -20°F | 10 km |
| 57256 | 4b | -25 to -20°F | 12 km |
| 57263 | 4b | -25 to -20°F | 19 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 USC00398116, at 45.3036, -97.0625, elevation 596 m (1,955 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 180.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wilmot (19 km)
- Waubay National Wild Life (25 km)
- Milbank 4 NW (31 km)
- Milbank (35 km)
- Webster (36 km)
- Rauville 2 W (37 km)
- Sisseton (40 km)
- Sisseton Muni Airport (41 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.