USDA zone 5a in Wisconsin
USDA plant hardiness zone 5a covers 64 locations across Wisconsin (average annual extreme minimum −20 to −15 °F): Ashland, WI, Avoca, WI, Baraboo, WI, Bayfield, WI, Beaver Dam, WI, Berlin, WI, and 58 more. Average last spring frost across this group ranges April 21 (Glen Haven) to May 31 (Port Wing), and growing seasons run 123–178 days (Port Wing to Glen Haven) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Wisconsin location's own frost dates; the printable planting calendar uses Steuben, this group's median-season location.
- USDA zone
- 5a−20 to −15 °F
- Last frost range
- Apr 21–May 31avg, 32°F
- First frost range
- Sep 29–Oct 18avg, 32°F
- Growing season range
- 123–178days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Ashland | — | Ashland Kennedy Mem Ap | May 23 | Sep 29 | 125 |
| Avoca | Spring Green, Plain, Gotham | Lone Rock Tri Co Ap | Apr 30 | Oct 9 | 161 |
| Baraboo | North Freedom, Merrimac | Baraboo | May 5 | Oct 5 | 152 |
| Bayfield | — | Madeline Island | May 20 | Oct 9 | 140 |
| Beaver Dam | Waupun, Columbus, Fall River, Fox Lake, Randolph, Friesland | Beaver Dam Wwtp | May 2 | Oct 9 | 157 |
| Berlin | — | Berlin Wwtp | May 1 | Oct 8 | 158 |
| Black Creek | — | Appleton | May 4 | Oct 6 | 154 |
| Boscobel | Fennimore, Blue River, Woodman | Boscobel Ap | May 3 | Oct 7 | 155 |
| Brodhead | Albany, Monticello, Davis, Juda | Brodhead Wwtp | Apr 29 | Oct 12 | 165 |
| Campbellsport | Rosendale, Oakfield, Brandon, Brownsville | Fond Du Lac Co Ap | May 1 | Oct 10 | 160 |
| Cashton | — | Cashton | Apr 27 | Oct 14 | 170 |
| Chain O' Lakes | Redgranite, King, Weyauwega, Wild Rose, Amherst, Pine River, +3 more | Waupaca | May 8 | Oct 6 | 151 |
| Clintonville | Marion, Manawa, Embarrass, Bear Creek, Nichols, Big Falls, +2 more | Clintonville | May 4 | Oct 6 | 154 |
| Darlington | Shullsburg | Darlington Wwtp | May 3 | Oct 4 | 153 |
| De Soto | Chaseburg, Stoddard, Eitzen, Genoa, New Albin | Genoa Dam 8 | Apr 22 | Oct 17 | 178 |
| Dodgeville | Mineral Point, Barneveld, Ridgeway, Arena, Highland, Cobb, +5 more | Dodgeville Wwtp | May 3 | Oct 7 | 157 |
| Eden | — | Fond Du Lac Wwtp | May 1 | Oct 12 | 162 |
| Gillett | Suring, Pound | Suring | May 14 | Oct 1 | 139 |
| Glen Haven | Garnavillo, North Buena Vista, Luxemburg, Osterdock, Holy Cross, Colesburg, +1 more | Guttenberg L&d 10 | Apr 21 | Oct 18 | 178 |
| Hartford | Slinger, Allenton, Iron Ridge, Neosho, Rubicon | Hartford Wwtp | May 8 | Oct 3 | 148 |
| Ixonia | Ashippun | Oconomowoc Wwtp | Apr 30 | Oct 12 | 164 |
| Kekoskee | Horicon, Lomira, Juneau, Hustisford, Theresa, Iron Ridge, +1 more | Horicon Wwtp | May 1 | Oct 10 | 158 |
| Keshena | Shawano, Bonduel, Gresham, Pulcifer | Shawano 2ssw | May 9 | Oct 2 | 144 |
| Kronenwetter | Mosinee | Wausau Dwtn Ap | May 6 | Oct 4 | 150 |
| La Crosse | West Salem, Coon Valley | La Crosse Wfo | Apr 27 | Oct 13 | 167 |
| Lancaster | Fennimore, Bloomington, Cassville, Tennyson, Mount Hope | Lancaster 4 Wsw | Apr 27 | Oct 11 | 166 |
| Lebanon | Clyman | Watertown Wwtp | Apr 28 | Oct 12 | 167 |
| Lodi | — | Lodi | May 1 | Oct 10 | 162 |
| Madison | Oregon | Uw Arboretum - Madison | May 1 | Oct 9 | 161 |
| Markesan | Fairwater | Markesan | May 8 | Oct 2 | 144 |
| Mauston | Lyndon Station, Elroy | Mauston 1 Se | May 2 | Oct 7 | 158 |
| Mazomanie | — | Mazomanie Wwtp | May 7 | Oct 1 | 148 |
| Middleton | Verona, Mount Horeb, Cross Plains, New Glarus, Belleville, Black Earth | Charmany Farm | Apr 28 | Oct 15 | 169 |
| Monroe | Browntown, Argyle, Woodford | Monroe Wwtp | Apr 27 | Oct 14 | 170 |
| Neshkoro | Montello, Green Lake, Westfield, Princeton, Kingston, Oxford, +3 more | Montello | May 3 | Oct 5 | 153 |
| New London | Hortonville, Dale, Fremont | New London | May 4 | Oct 6 | 153 |
| New Odanah | — | Saxon 1wsw | May 23 | Oct 1 | 132 |
| Norwalk | Wilton, Rockland | Sparta | May 9 | Oct 1 | 144 |
| Oconto | Oconto Falls, Coleman, Sobieski, Krakow, Lena, Abrams | Oconto 4 W | May 9 | Oct 6 | 150 |
| Onalaska | Holmen, La Crescent, French Island | La Crosse Muni Ap | Apr 23 | Oct 17 | 177 |
| Peshtigo | Crivitz, Stephenson | Marinette | May 4 | Oct 11 | 160 |
| Platteville | Livingston, Belmont, Rewey | Platteville | Apr 30 | Oct 13 | 166 |
| Port Wing | — | Port Wing | May 31 | Oct 2 | 123 |
| Portage | Pardeeville, Wyocena, Cambria, Endeavor | Portage Wwtp | Apr 28 | Oct 10 | 164 |
| Potter | — | Brillion | May 6 | Oct 6 | 151 |
| Prairie du Chien | Marquette, Monona, McGregor, Bagley, Farmersburg, Patch Grove | Prairie Du Chien | Apr 28 | Oct 12 | 166 |
| Prairie du Sac | Sauk | Sauk City Wwtp | May 4 | Oct 6 | 155 |
| Pulaski | Seymour | Green Bay | Apr 30 | Oct 9 | 161 |
| Reedsburg | Rock Springs, Lime Ridge, La Valle, Loganville | Reedsburg | May 2 | Oct 7 | 156 |
| Richfield | — | Germantown | May 6 | Oct 8 | 154 |
| Richland Center | Muscoda, Lime Ridge, Cazenovia | Richland Ctr | May 5 | Oct 6 | 154 |
| Ripon | — | Ripon 5 Ne | May 1 | Oct 11 | 163 |
| Steuben * | Bell Center, Soldiers Grove, Ferryville, Mount Sterling, Seneca | Gays Mills | May 3 | Oct 7 | 156 |
| Stevens Point | Nelsonville | Stevens Pt | May 4 | Oct 7 | 155 |
| Sun Prairie | DeForest, Waunakee | Madison Dane Rgnl Ap | May 1 | Oct 10 | 160 |
| Tigerton | Iola | Rosholt 9 Nne | May 6 | Oct 5 | 150 |
| Trempealeau | Dakota | Trempealeau Dam 6 | Apr 29 | Oct 11 | 165 |
| Viroqua | Westby, Readstown, Viola | Viroqua | May 7 | Oct 2 | 148 |
| Waukau | — | Oshkosh Wittman Ap | Apr 30 | Oct 13 | 165 |
| Wautoma | — | Hancock Exp Farm | May 10 | Oct 3 | 146 |
| Wauzeka | Lynxville, Lansing, Harpers Ferry, Waterville | Lynxville Dam 9 | Apr 24 | Oct 17 | 175 |
| Windsor | DeForest, Doylestown, Poynette, Rio, Dane, Arlington | Arlington | May 4 | Oct 6 | 154 |
| Wisconsin Dells | Lake Delton, Briggsville | Wisconsin Dells | May 8 | Oct 3 | 146 |
| Wonewoc | Kendall | Hillsboro | May 5 | Oct 4 | 153 |
* Steuben is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Steuben, representative)
Computed from Steuben's average frost dates — the median-season location in this Wisconsinzone 5a group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Mar 8 – Mar 22 | May 10 – May 17 | Jul 9 – Jul 29 | — | matures comfortably |
| Pepper | Very tender | Feb 22 – Mar 8 | May 17 – May 24 | Jul 16 – Aug 15 | — | matures comfortably |
| Cucumber | Tender | Apr 5 – Apr 12 | May 10 – May 17 | Jun 29 – Jul 19 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | May 10 – May 17 | Jun 24 – Jul 9 | — | matures comfortably |
| Bush bean | Tender | — | May 10 – May 17 | Jun 29 – Jul 9 | Aug 8 – Aug 18 | matures comfortably |
| Sweet corn | Tender | — | May 3 – May 17 | Jul 2 – Aug 1 | — | matures comfortably |
| Basil | Very tender | Mar 22 – Apr 5 | May 10 – May 17 | Jun 9 – Jun 24 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 22 – Apr 5 | Apr 5 – Apr 19 | May 20 – Jun 4 | Jul 25 – Aug 9 | matures comfortably |
| Pea | Hardy | — | Mar 22 – Apr 5 | May 16 – May 31 | Jul 15 – Jul 30 | matures comfortably |
| Spinach | Hardy | — | Mar 22 – Apr 5 | May 1 – May 11 | Aug 4 – Aug 14 | matures comfortably |
| Carrot | Half-hardy | — | Apr 12 – Apr 19 | Jun 11 – Jul 1 | Jul 5 – Jul 25 | matures comfortably |
| Broccoli | Half-hardy | Mar 8 – Mar 22 | Apr 5 – Apr 19 | May 30 – Jun 19 | Jul 10 – Jul 30 | matures comfortably |
Which crops fit this growing season
Using Steuben's own 156-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Steuben)
From NOAA's 1991–2020 Climate Normals at station USC00473022. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 13 | May 28 | Sep 29 | Oct 11 | 139 |
| 32°F (freeze) | May 3 | May 18 | Oct 7 | Oct 20 | 156 |
| 28°F | Apr 24 | May 9 | Oct 18 | Oct 31 | 175 |
| 24°F | Apr 11 | Apr 30 | Oct 28 | Nov 10 | 197 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 64 locations is 2,520; Steuben's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,694 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,678 | cool-season crops (brassicas, greens) |
Hardiness zone 5a in Wisconsin
Zone 5a means an average annual extreme minimum winter temperature of about −20 to −15 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Wisconsin spans 5 hardiness zones in this dataset — see all Wisconsin locations for the full range, including zones4a, 4b, 5b, 6a.
Explore zone 5a in other states at zone 5a, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 5a mean in Wisconsin?
- Zone 5a means an average annual extreme minimum winter temperature of −20 to −15 °F — the standard USDA measure of which perennials survive winter. 64 locations in Wisconsin fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Wisconsin's zone 5a is the growing season longest?
- Glen Haven runs the longest season on this page at about 178 days; Port Wing is shortest at about 123 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Wisconsin's zone 5a?
- Using Steuben's frost dates (this page's median-season location): start seeds indoors about Mar 8 – Mar 22, then transplant outside about May 10 – May 17. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Wisconsin's zone 5a have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 64 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.