Frost dates for Cotton, MN
At Cotton, the median last spring frost (32°F) is May 27 and the median first fall frost is Sep 20, for a typical growing season of 115 days. For a 90% chance that the last frost has passed, wait until Jun 11. Nearby ZIP codes are in USDA hardiness zones 3b to 4a.
- May 27Last spring frost (median)50% chance of 32°F after this date
- Jun 11Safer planting date10% chance of 32°F after this date
- Sep 20First fall frost (median)50% chance of 32°F by this date
- 115 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 |
|---|---|---|---|
| 32°F | May 9 | May 27 | Jun 11 |
| 28°F | Apr 30 | May 14 | May 31 |
| 24°F | Apr 20 | May 2 | May 20 |
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 |
|---|---|---|---|
| 32°F | Sep 4 | Sep 20 | Oct 3 |
| 28°F | Sep 16 | Oct 1 | Oct 16 |
| 24°F | Sep 26 | Oct 12 | Oct 29 |
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 | 60 days | 88 days | 112 days |
| 32°F | 92 days | 115 days | 137 days |
| 28°F | 116 days | 139 days | 160 days |
| 24°F | 139 days | 161 days | 180 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 |
|---|---|---|---|
| 55724 | 3b | -35 to -30°F | 7 km |
| 55717 | 4a | -30 to -25°F | 12 km |
| 55738 | 3b | -35 to -30°F | 18 km |
| 55763 | 3b | -35 to -30°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 USC00211840, at 47.1686, -92.4628, elevation 403 m (1,323 ft).
- Data quality: Representative (10+ years), 12 years of freeze data.
- Average days per year at or below 32°F: 207.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Eveleth Wastewater Plant (33 km)
- Island Lake 4e (34 km)
- Hibbing Chisholm Hibbing Airport (37 km)
- Floodwood 3 NE (38 km)
- Duluth NWS (42 km)
- Duluth (42 km)
- Brimson 2s (46 km)
- Cloquet (52 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.