Frost dates for Alexandria, SD
At Alexandria, the median last spring frost (32°F) is May 8 and the median first fall frost is Sep 29, for a typical growing season of 143 days. For a 90% chance that the last frost has passed, wait until May 21. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 8Last spring frost (median)50% chance of 32°F after this date
- May 21Safer planting date10% chance of 32°F after this date
- Sep 29First fall frost (median)50% chance of 32°F by this date
- 143 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 5 | May 18 | May 31 |
| 32°F | Apr 27 | May 8 | May 21 |
| 28°F | Apr 15 | Apr 30 | May 13 |
| 24°F | Apr 6 | Apr 21 | May 4 |
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 9 | Sep 22 | Oct 2 |
| 32°F | Sep 17 | Sep 29 | Oct 11 |
| 28°F | Sep 24 | Oct 7 | Oct 20 |
| 24°F | Oct 2 | Oct 17 | Oct 30 |
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 | 106 days | 126 days | 143 days |
| 32°F | 126 days | 143 days | 160 days |
| 28°F | 143 days | 161 days | 179 days |
| 24°F | 159 days | 180 days | 200 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 |
|---|---|---|---|
| 57311 | 5a | -20 to -15°F | 3 km |
| 57374 | 5a | -20 to -15°F | 20 km |
| 57334 | 5a | -20 to -15°F | 21 km |
| 57331 | 5a | -20 to -15°F | 28 km |
| 57366 | 5a | -20 to -15°F | 31 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 USC00390128, at 43.6514, -97.7981, elevation 416 m (1,365 ft).
- Data quality: Standard (24+ years of data), 29 years of freeze data.
- Average days per year at or below 32°F: 159.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mitchell 2 N (21 km)
- Mitchell Muni Airport (23 km)
- Mitchell (25 km)
- Bridgewater (26 km)
- Salem 5ne (41 km)
- Howard (45 km)
- Menno (50 km)
- Winfred 2s (51 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.