Frost dates for Green Bay WFO, WI
At Green Bay WFO, the median last spring frost (32°F) is May 1 and the median first fall frost is Oct 11, for a typical growing season of 160 days. For a 90% chance that the last frost has passed, wait until May 16. Nearby ZIP codes are in USDA hardiness zones 5a to 5b.
- May 1Last spring frost (median)50% chance of 32°F after this date
- May 16Safer planting date10% chance of 32°F after this date
- Oct 11First 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 14 | May 29 |
| 32°F | Apr 19 | May 1 | May 16 |
| 28°F | Apr 6 | Apr 20 | May 4 |
| 24°F | Mar 24 | Apr 7 | Apr 21 |
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 18 | Sep 30 | Oct 13 |
| 32°F | Sep 26 | Oct 11 | Oct 26 |
| 28°F | Oct 10 | Oct 25 | Nov 6 |
| 24°F | Oct 24 | Nov 5 | Nov 19 |
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 | 118 days | 137 days | 158 days |
| 32°F | 140 days | 160 days | 182 days |
| 28°F | 165 days | 186 days | 206 days |
| 24°F | 191 days | 211 days | 230 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 |
|---|---|---|---|
| 54155 | 5b | -15 to -10°F | 8 km |
| 54165 | 5a | -20 to -15°F | 16 km |
| 54180 | 5b | -15 to -10°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 USC00473268, at 44.4983, -88.1119, elevation 208 m (682 ft).
- Data quality: Representative (10+ years), 15 years of freeze data.
- Average days per year at or below 32°F: 151.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Green Bay (0 km)
- Green Bay Botanical (4 km)
- Denmark Wastewater Plant (29 km)
- Appleton (36 km)
- Brillion (38 km)
- Oconto 4 W (45 km)
- Kewaunee (48 km)
- Shawano 2ssw (50 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.