Frost dates for Roy Lake, SD
At Roy Lake, the median last spring frost (32°F) is May 2 and the median first fall frost is Oct 9, for a typical growing season of 160 days. For a 90% chance that the last frost has passed, wait until May 15. Nearby ZIP codes are in USDA hardiness zones 4a to 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 9First fall frost (median)50% chance of 32°F by this date
- 160 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 19 | May 2 | May 15 |
| 28°F | Apr 8 | Apr 24 | May 6 |
| 24°F | Apr 2 | Apr 15 | 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 20 | Oct 1 | Oct 14 |
| 32°F | Sep 27 | Oct 9 | Oct 22 |
| 28°F | Oct 5 | Oct 20 | Nov 1 |
| 24°F | Oct 14 | Oct 29 | Nov 11 |
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 | 125 days | 141 days | 160 days |
| 32°F | 143 days | 160 days | 177 days |
| 28°F | 159 days | 178 days | 197 days |
| 24°F | 175 days | 196 days | 215 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 |
|---|---|---|---|
| 57247 | 4a | -30 to -25°F | 2 km |
| 57232 | 4b | -25 to -20°F | 10 km |
| 57270 | 4b | -25 to -20°F | 18 km |
| 57261 | 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 USC00397326, at 45.7086, -97.4339, elevation 552 m (1,810 ft).
- Data quality: Representative (10+ years), 19 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
- Britton (26 km)
- Sisseton (31 km)
- Waubay National Wild Life (33 km)
- Sisseton Muni Airport (35 km)
- Webster (42 km)
- Andover #2 (49 km)
- Victor 4 N (52 km)
- Summit 1 W (54 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.