What Planting Zones Are in Wisconsin?
Wisconsin spans USDA hardiness zones 3b to 6a, where the average coldest winter night ranges from −35 °F to −5 °F (−37.2 °C to −20.6 °C). Zone 5b covers the most ZIP codes, 30%, and zones 4b to 5b together cover 86% of the state.
- Zone 3b<1% · 1 ZIP
- Zone 4a8% · 73 ZIPs
- Zone 4b27% · 238 ZIPs
- Zone 5a29% · 250 ZIPs
- Zone 5b30% · 263 ZIPs
- Zone 6a5% · 47 ZIPs
Bars show each zone's share of the 872 Wisconsin ZIP codes in the official 2023 USDA ZIP code table; select a zone for its temperatures and hardy plants.
What Hardiness Zone Are Wisconsin Cities In?
Milwaukee is in zone 6a, Madison is in zone 5a, Green Bay is in zone 5b and Kenosha is in zone 5b. The table lists the zone, winter low and average frost dates for 19 Wisconsin cities, using the ZIP code nearest each city center.
| City | ZIP | Zone | Winter low | Last frost | First frost |
|---|---|---|---|---|---|
| Milwaukee | 53210 | 6a | −10 °F to −5 °F | Apr 26 | Oct 18 |
| Madison | 53792 | 5a | −20 °F to −15 °F | May 1 | Oct 9 |
| Green Bay | 54302 | 5b | −15 °F to −10 °F | May 7 | Oct 9 |
| Kenosha | 53142 | 5b | −15 °F to −10 °F | Apr 28 | Oct 19 |
| Racine | 53405 | 6a | −10 °F to −5 °F | Apr 24 | Oct 24 |
| Appleton | 54911 | 5b | −15 °F to −10 °F | May 4 | Oct 6 |
| Eau Claire | 54703 | 4b | −25 °F to −20 °F | May 8 | Oct 4 |
| Waukesha | 53186 | 5b | −15 °F to −10 °F | Apr 30 | Oct 14 |
| Oshkosh | 54901 | 5b | −15 °F to −10 °F | Apr 24 | Oct 20 |
| Janesville | 53545 | 5b | −15 °F to −10 °F | Apr 26 | Oct 15 |
| La Crosse | 54603 | 5a | −20 °F to −15 °F | Apr 23 | Oct 17 |
| Sheboygan | 53081 | 6a | −10 °F to −5 °F | May 2 | Oct 21 |
| Fond du Lac | 54935 | 5b | −15 °F to −10 °F | May 1 | Oct 12 |
| Wausau | 54401 | 4b | −25 °F to −20 °F | May 6 | Oct 4 |
| Manitowoc | 54220 | 5b | −15 °F to −10 °F | Apr 30 | Oct 20 |
| West Bend | 53095 | 5b | −15 °F to −10 °F | May 1 | Oct 12 |
| Superior | 54880 | 4b | −25 °F to −20 °F | May 18 | Oct 3 |
| Stevens Point | 54482 | 4b | −25 °F to −20 °F | May 4 | Oct 7 |
| Medford | 54451 | 4a | −30 °F to −25 °F | May 11 | Oct 1 |
Zone: 2023 USDA ZIP code table for the ZIP code nearest each city's Census center point. Frost dates: 50% (median) dates from the nearest NOAA station, 1991–2020 normals. Cities: the largest Wisconsin places by 2024 Census population estimates, spread across the state, plus the largest place in each common zone. Large cities can span two half zones.
Which Parts of Wisconsin Are in Each Zone?
Zone 4a, the coldest Wisconsin zone with towns, covers 8% of ZIP codes around Medford, Tomahawk and Ladysmith. Zone 6a, the warmest, covers 5% around Milwaukee, Racine and Sheboygan. The table lists the largest places in every zone.
| Zone | Avg. coldest night | Share of ZIPs | Largest places in this zone |
|---|---|---|---|
| Zone 3b | −35 °F to −30 °F | <1% (1) | Rural ZIP codes only |
| Zone 4a | −30 °F to −25 °F | 8% (73) | Medford, Tomahawk, Ladysmith, Hayward |
| Zone 4b | −25 °F to −20 °F | 27% (238) | Eau Claire, Wausau, Superior, Stevens Point |
| Zone 5a | −20 °F to −15 °F | 29% (250) | Madison, La Crosse, Sun Prairie, Middleton |
| Zone 5b | −15 °F to −10 °F | 30% (263) | Green Bay, Kenosha, Appleton, Waukesha |
| Zone 6a | −10 °F to −5 °F | 5% (47) | Milwaukee, Racine, Sheboygan, Oak Creek |
Places: incorporated places with 1,000+ residents, assigned the zone of the ZIP code nearest their Census center point.
What Do the Hardiness Zones Mean for Wisconsin Gardeners?
A Wisconsin gardener in zone 6a sees winter lows about 25 °F milder than one in zone 3b, so a shrub or perennial that thrives in one part of the state can die in another. Choose plants rated to your own ZIP code's zone or colder.
Hardiness zones follow latitude, elevation and large bodies of water rather than state lines. Higher ground and inland valleys that trap cold air usually sit in colder half zones, while cities, coasts and large lakes moderate winter lows. Within Wisconsin, a plant labelled “zones 4–5” survives winter in at least 86% of ZIP codes, but plants at the edge of their range benefit from mulch and a sheltered spot. Enter a ZIP code in the USDA hardiness zone finder by ZIP code to check your exact half zone before buying perennials.
A zone describes winter cold only. Summer heat, humidity, rainfall and soil decide whether a cold-hardy plant thrives, and planting dates for vegetables follow frost dates, not zones: two Wisconsin towns in the same zone can have last frosts weeks apart.
What Plants Grow Well Across Wisconsin?
154 plants in PlantoScan's catalogue are hardy in every zone from 4b to 5b, the zones that cover 86% of Wisconsin ZIP codes. Popular examples include peony, daisy and poppy.
Peony
Paeonia lactiflora
Zone 3 – 8
AI generated
- DaisyBellis perennisPlantoScan
Daisy
Bellis perennis
Zone 4a – 8b
Poppy
Papaver somniferum
Zone 3a – 9b
AI generated
Daffodil
Narcissus poeticus
Zone 3 – 8
AI generated
Alfalfa
Medicago sativa
Zone 3a – 10a
AI generated
Hyacinth
Hyacinthus orientalis
Zone 4 – 8
AI generated
Tiger Lily
Lilium lancifolium
Zone 3 – 8
AI generated
Forget Me Not
Myosotis sylvatica
Zone 3 – 8
AI generated
Lemon Balm
Melissa officinalis
Zone 4a – 9b
Image: PlantoScan
Hardiness ranges come from PlantoScan's plant database; gardeners in Wisconsin's colder or warmer edge zones should check each plant's full range.
When Is the Last Frost in Wisconsin?
Across most Wisconsin ZIP codes, the average last spring frost falls between April 26 and May 19, from April 23 in La Crosse to May 18 in Superior. Tender vegetables such as tomatoes go out 1 to 2 weeks after the local date.
The last and first frost dates for Wisconsin cities include the safer 90% planting date, the fall frost date, growing season length and a tomato planting table for each city.
Frequently Asked Questions
- What planting zone is Wisconsin?
- Wisconsin spans USDA hardiness zones 3b to 6a on the 2023 USDA Plant Hardiness Zone Map. Zone 5b is the most common, covering 30% of the state's 872 ZIP codes, and zones 4b to 5b together cover 86%.
- What hardiness zone is Milwaukee, Wisconsin?
- Milwaukee is in USDA hardiness zone 6a (ZIP 53210), where the average coldest winter night reaches −10 °F to −5 °F. Its average last spring frost is April 26 and its first fall frost October 18.
- What hardiness zone is Madison, Wisconsin?
- Madison is in USDA hardiness zone 5a (ZIP 53792), where the average coldest winter night reaches −20 °F to −15 °F. Its average last spring frost is May 1 and its first fall frost October 9.
- What hardiness zone is Green Bay, Wisconsin?
- Green Bay is in USDA hardiness zone 5b (ZIP 54302), where the average coldest winter night reaches −15 °F to −10 °F. Its average last spring frost is May 7 and its first fall frost October 9.
- What is the coldest hardiness zone in Wisconsin?
- Zone 3b (−35 °F to −30 °F) is the coldest zone in Wisconsin, found in 1 ZIP code. The warmest is zone 6a (−10 °F to −5 °F), around Milwaukee and Racine.
Zones: 2023 USDA Plant Hardiness Zone Map ZIP code table, USDA Agricultural Research Service and the PRISM Climate Group, Oregon State University, used without changes. Frost dates: NOAA National Centers for Environmental Information, 1991–2020 U.S. Climate Normals. City locations and populations: U.S. Census Bureau Gazetteer files and Vintage 2024 population estimates. PlantoScan is not affiliated with or endorsed by these agencies.