Frost dates for Madeline Island, WI
At Madeline Island, the median last spring frost (32°F) is May 20 and the median first fall frost is Oct 9, for a typical growing season of 140 days. For a 90% chance that the last frost has passed, wait until Jun 3. Nearby ZIP codes are in USDA hardiness zones 4b to 5b.
- May 20Last spring frost (median)50% chance of 32°F after this date
- Jun 3Safer planting date10% chance of 32°F after this date
- Oct 9First fall frost (median)50% chance of 32°F by this date
- 140 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 20 | Jun 1 | Jun 13 |
| 32°F | May 5 | May 20 | Jun 3 |
| 28°F | Apr 24 | May 6 | May 21 |
| 24°F | Apr 10 | Apr 24 | May 8 |
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 17 | Sep 29 | Oct 11 |
| 32°F | Sep 25 | Oct 9 | Oct 23 |
| 28°F | Oct 6 | Oct 23 | Nov 4 |
| 24°F | Oct 21 | Nov 3 | Nov 17 |
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 | 100 days | 118 days | 135 days |
| 32°F | 120 days | 140 days | 161 days |
| 28°F | 144 days | 166 days | 186 days |
| 24°F | 171 days | 191 days | 212 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 54814 | 5a | -20 to -15°F | 14 km |
| 54891 | 4b | -25 to -20°F | 18 km |
| 54861 | 5a | -20 to -15°F | 22 km |
| 54850 | 5b | -15 to -10°F | 23 km |
| 54806 | 5a | -20 to -15°F | 26 km |
| 54827 | 4b | -25 to -20°F | 26 km |
| 54844 | 4b | -25 to -20°F | 34 km |
| 54559 | 4b | -25 to -20°F | 38 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 USC00474953, at 46.7781, -90.7653, elevation 201 m (660 ft).
- Data quality: Standard (24+ years of data), 29 years of freeze data.
- Average days per year at or below 32°F: 181.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Bayfield Fish Hatchery (8 km)
- Bayfield 6 N (12 km)
- Ashland 3s (28 km)
- Ashland Kennedy Mem Airport (28 km)
- Saxon 1wsw (41 km)
- Mellen 4 NE (46 km)
- Port Wing (47 km)
- Hurley (56 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.