Frost dates for Theodore Roosevelt Airport, ND
At Theodore Roosevelt Airport, the median last spring frost (32°F) is May 18 and the median first fall frost is Sep 25, for a typical growing season of 129 days. For a 90% chance that the last frost has passed, wait until May 31. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 18Last spring frost (median)50% chance of 32°F after this date
- May 31Safer planting date10% chance of 32°F after this date
- Sep 25First fall frost (median)50% chance of 32°F by this date
- 129 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 16 | May 29 | Jun 12 |
| 32°F | May 6 | May 18 | May 31 |
| 28°F | Apr 26 | May 8 | May 22 |
| 24°F | Apr 13 | Apr 28 | May 10 |
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 3 | Sep 16 | Sep 28 |
| 32°F | Sep 12 | Sep 25 | Oct 7 |
| 28°F | Sep 22 | Oct 3 | Oct 16 |
| 24°F | Sep 28 | Oct 12 | Oct 25 |
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 | 89 days | 109 days | 127 days |
| 32°F | 110 days | 129 days | 146 days |
| 28°F | 129 days | 147 days | 166 days |
| 24°F | 146 days | 166 days | 185 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 |
|---|---|---|---|
| 58655 | 4b | -25 to -20°F | 18 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 USW00024012, at 46.7994, -102.7972, elevation 786 m (2,580 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 189.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Dickinson (10 km)
- New England (29 km)
- Taylor 7 NNW (33 km)
- Richardton Abbey (38 km)
- Dickinson Rch HQ (44 km)
- Medora 7 E (45 km)
- Amidon (53 km)
- Fairfield (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.