Frost dates for Boscobel Airport, WI
At Boscobel Airport, the median last spring frost (32°F) is May 3 and the median first fall frost is Oct 7, for a typical growing season of 155 days. For a 90% chance that the last frost has passed, wait until May 18. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 3Last spring frost (median)50% chance of 32°F after this date
- May 18Safer planting date10% chance of 32°F after this date
- Oct 7First fall frost (median)50% chance of 32°F by this date
- 155 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 28 |
| 32°F | Apr 19 | May 3 | May 18 |
| 28°F | Apr 7 | Apr 22 | May 8 |
| 24°F | Mar 28 | Apr 10 | Apr 27 |
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 7 | Oct 20 |
| 28°F | Oct 4 | Oct 17 | Oct 31 |
| 24°F | Oct 13 | Oct 27 | Nov 10 |
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 | 136 days | 154 days |
| 32°F | 138 days | 155 days | 176 days |
| 28°F | 157 days | 177 days | 198 days |
| 24°F | 178 days | 200 days | 220 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 |
|---|---|---|---|
| 53805 | 5a | -20 to -15°F | 2 km |
| 53518 | 5a | -20 to -15°F | 12 km |
| 53809 | 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 USW00094994, at 43.1561, -90.6775, elevation 205 m (672 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 152.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Steuben 4 SE (13 km)
- Gays Mills (22 km)
- Richland Center (30 km)
- Lynxville Dam 9 (35 km)
- Lancaster 4 WSW (38 km)
- Prairie Du Chien (39 km)
- Lone Rock Tri Co Airport (41 km)
- Viroqua (48 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.