Frost dates for Ontonagon 6 SE, MI
At Ontonagon 6 SE, the median last spring frost (32°F) is May 27 and the median first fall frost is Oct 1, for a typical growing season of 127 days. For a 90% chance that the last frost has passed, wait until Jun 13. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 27Last spring frost (median)50% chance of 32°F after this date
- Jun 13Safer planting date10% chance of 32°F after this date
- Oct 1First fall frost (median)50% chance of 32°F by this date
- 127 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 24 | Jun 8 | Jul 1 |
| 32°F | May 7 | May 27 | Jun 13 |
| 28°F | Apr 25 | May 10 | May 29 |
| 24°F | Apr 12 | Apr 28 | May 14 |
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 | Aug 26 | Sep 17 | Oct 3 |
| 32°F | Sep 14 | Oct 1 | Oct 16 |
| 28°F | Sep 28 | Oct 14 | Nov 1 |
| 24°F | Oct 11 | Oct 31 | 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 | 65 days | 98 days | 123 days |
| 32°F | 102 days | 127 days | 151 days |
| 28°F | 130 days | 157 days | 180 days |
| 24°F | 159 days | 184 days | 205 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 |
|---|---|---|---|
| 49960 | 4b | -25 to -20°F | 14 km |
| 49953 | 5a | -20 to -15°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 USC00206220, at 46.8342, -89.2075, elevation 241 m (790 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 175.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Greenland 6n (9 km)
- Bergland Dam (38 km)
- Baraga 7nw (46 km)
- Paulding (49 km)
- Watton 2wsw (55 km)
- Alberta Ford For Center (59 km)
- Covington 1nnw (59 km)
- Jacobsville (62 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.