Frost dates for Milbank 4 NW, SD
At Milbank 4 NW, the median last spring frost (32°F) is May 2 and the median first fall frost is Oct 4, for a typical growing season of 153 days. For a 90% chance that the last frost has passed, wait until May 15. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 2Last spring frost (median)50% chance of 32°F after this date
- May 15Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 153 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 | Apr 30 | May 11 | May 24 |
| 32°F | Apr 20 | May 2 | May 15 |
| 28°F | Apr 10 | Apr 24 | May 5 |
| 24°F | Apr 2 | Apr 14 | Apr 29 |
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 13 | Sep 26 | Oct 6 |
| 32°F | Sep 22 | Oct 4 | Oct 16 |
| 28°F | Sep 30 | Oct 12 | Oct 25 |
| 24°F | Oct 8 | Oct 23 | Nov 6 |
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 | 116 days | 135 days | 152 days |
| 32°F | 135 days | 153 days | 170 days |
| 28°F | 151 days | 171 days | 190 days |
| 24°F | 171 days | 190 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 |
|---|---|---|---|
| 57216 | 4b | -25 to -20°F | 11 km |
| 57269 | 4b | -25 to -20°F | 12 km |
| 56225 | 4b | -25 to -20°F | 25 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 USC00395536, at 45.2836, -96.6689, elevation 349 m (1,145 ft).
- Data quality: Representative (10+ years), 13 years of freeze data.
- Average days per year at or below 32°F: 174.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Milbank (7 km)
- Wilmot (20 km)
- Summit 1 W (31 km)
- Sisseton Muni Airport (50 km)
- Rauville 2 W (51 km)
- Sisseton (51 km)
- Waubay National Wild Life (54 km)
- Watertown Regional Airport (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.