Wisconsin frost dates
Across 203 weather stations in Wisconsin, the median last spring frost runs from Apr 19 in Kenosha to Jun 3 in North Pelican, and the first fall frost from Sep 18 to Oct 29.
Wisconsin at a glance
- Weather stations
- 203
- Earliest last frost
- Apr 19 Kenosha
- Latest last frost
- Jun 3 North Pelican
- Longest season
- 192 days Milwaukee Mitchell Airport
- Typical season
- about 154 frost-free days
- Hardiness zones
- Zones 4a to 6a
Frost dates by weather station
| Weather station | Last spring frost | First fall frost | Frost-free days | Zone |
|---|---|---|---|---|
| Afton - Janesville Wastewater Plant | Apr 26 | Oct 15 | 170 | 5b |
| Alma Dam | Apr 28 | Oct 14 | 168 | 4b |
| Amery | May 5 | Oct 4 | 151 | 4b |
| Antigo | May 14 | Sep 30 | 139 | 4b |
| Appleton | May 4 | Oct 6 | 154 | 5b |
| Arlington | May 4 | Oct 6 | 154 | 5a |
| Ashland | May 20 | Oct 2 | 133 | 5a |
| Ashland Kennedy Memorial Airport | May 23 | Sep 29 | 125 | 5a |
| Augusta Ranger Station | May 7 | Oct 1 | 146 | 4b |
| Baldwin | May 6 | Oct 2 | 148 | 4b |
| Baraboo | May 5 | Oct 5 | 152 | 5a |
| Bayfield | May 20 | Oct 8 | 141 | 5a |
| Bayfield Fish Hatchery | May 23 | Oct 2 | 131 | 5a |
| Beaver Dam Wastewater Plant | May 2 | Oct 9 | 157 | 5a |
| Belgium Wastewater Plant | May 5 | Oct 12 | 159 | 5b |
| Beloit | May 1 | Oct 12 | 162 | 5b |
| Berlin Wastewater Plant | May 1 | Oct 8 | 158 | 5a |
| Big Falls Hydro | May 7 | Oct 3 | 147 | 4a |
| Blair | May 9 | Oct 1 | 143 | 4b |
| Bloomer | May 5 | Oct 3 | 151 | 4b |
| Boscobel Airport | May 3 | Oct 7 | 155 | 5a |
| Brillion | May 6 | Oct 6 | 151 | 5b |
| Brodhead Wastewater Plant | Apr 29 | Oct 12 | 165 | 5a |
| Brookfield Wastewater Plant | Apr 30 | Oct 14 | 164 | 5b |
| Brule Ranger Station | May 24 | Sep 26 | 124 | 4a |
| Burlington | May 5 | Oct 9 | 156 | 5b |
| Butternut | May 22 | Sep 24 | 126 | 4a |
| Cashton | Apr 27 | Oct 14 | 170 | 5a |
| Cashton 3 mi NNW | May 6 | Oct 3 | 150 | 5a |
| Charmany Farm | Apr 28 | Oct 15 | 169 | 5b |
| Chilton | May 1 | Oct 14 | 162 | 5b |
| Clam Lake | May 16 | Sep 30 | 136 | 4a |
| Clinton Wastewater Plant | Apr 30 | Oct 10 | 161 | 5b |
| Clintonville | May 4 | Oct 6 | 154 | 5a |
| Crivitz High Falls | May 26 | Sep 22 | 118 | 4b |
| Cumberland | May 5 | Oct 4 | 152 | 4b |
| Dalton | May 6 | Oct 2 | 150 | 5a |
| Danbury | May 11 | Sep 30 | 138 | 4a |
| Darlington Wastewater Plant | May 3 | Oct 4 | 153 | 5a |
| Delavan Wastewater Plant | Apr 28 | Oct 14 | 168 | 5b |
| Denmark Wastewater Plant | May 6 | Oct 12 | 158 | 5b |
| Dodge | May 5 | Oct 5 | 152 | 4b |
| Dodgeville Wastewater Plant | May 3 | Oct 7 | 157 | 5a |
| Drummond | May 20 | Oct 1 | 132 | 4a |
| Durand | May 1 | Oct 10 | 162 | 4b |
| Eagle River | May 25 | Sep 24 | 121 | 4b |
| Eau Claire | Apr 24 | Oct 14 | 170 | 4b |
| Eau Claire Regional Airport | May 8 | Oct 4 | 149 | 4b |
| Ellsworth | May 13 | Sep 29 | 139 | 4b |
| Ephraim -Wwtp | May 14 | Oct 18 | 155 | 5b |
| Florence | May 24 | Sep 25 | 121 | 4b |
| Fond du Lac | Apr 27 | Oct 19 | 174 | 5b |
| Fond du Lac County Airport | May 1 | Oct 10 | 160 | 5b |
| Fond du Lac Wastewater Plant | May 1 | Oct 12 | 162 | 5b |
| Forestville- | May 6 | Oct 17 | 163 | 5b |
| Fort Atkinson | Apr 28 | Oct 13 | 166 | 5b |
| Foxboro | Jun 1 | Sep 22 | 113 | 4a |
| Friendship | May 9 | Oct 3 | 147 | 4b |
| Gays Mills | May 3 | Oct 7 | 156 | 5a |
| Genoa Dam | Apr 22 | Oct 17 | 178 | 5a |
| Germantown | May 6 | Oct 8 | 154 | 5b |
| Goodman Sanitary District | May 24 | Sep 30 | 128 | 4b |
| Gordon | May 22 | Sep 26 | 126 | 4a |
| Grafton Wastewater Plant | Apr 23 | Oct 24 | 182 | 6a |
| Grantsburg | May 11 | Oct 1 | 141 | 4a |
| Green Bay | Apr 30 | Oct 9 | 161 | 5b |
| Green Bay Botanical | May 7 | Oct 9 | 154 | 5b |
| Hales Corners/Whitnall Park/Bo | May 3 | Oct 14 | 162 | 5b |
| Hancock Experiment Farm | May 10 | Oct 3 | 146 | 4b |
| Hartford Wastewater Plant | May 8 | Oct 3 | 148 | 5a |
| Hayward Municipal Airport | May 23 | Sep 22 | 122 | 4a |
| Hayward Ranger Station | May 22 | Sep 23 | 124 | 4a |
| Hillsboro | May 5 | Oct 4 | 153 | 4b |
| Hillsboro 2 mi SW | May 12 | Sep 29 | 138 | 4b |
| Hingham Wastewater Plant | May 3 | Oct 16 | 165 | 5b |
| Holcombe | May 5 | Oct 2 | 149 | 4b |
| Horicon Wastewater Plant | May 1 | Oct 10 | 158 | 5a |
| Hurley | May 24 | Sep 28 | 128 | 4b |
| Hustisford Wastewater Plant | Apr 28 | Oct 10 | 164 | 5a |
| Jackson | Apr 30 | Oct 15 | 167 | 5b |
| Jefferson Wastewater Plant | Apr 25 | Oct 18 | 173 | 5b |
| Jim Falls | May 1 | Oct 8 | 158 | 4b |
| Jump River | May 20 | Sep 23 | 125 | 4a |
| Kenosha | Apr 19 | Oct 26 | 189 | 6a |
| Kenosha Regional Airport | Apr 28 | Oct 19 | 174 | 5b |
| Kewaunee | May 1 | Oct 18 | 168 | 5b |
| La Crosse | Apr 27 | Oct 13 | 167 | 5a |
| La Crosse Municipal Airport | Apr 23 | Oct 17 | 177 | 5a |
| Ladysmith | May 27 | Sep 22 | 117 | 4a |
| Lake Geneva Wastewater Plant | Apr 25 | Oct 21 | 179 | 5b |
| Lake Mills Wastewater Plant | Apr 29 | Oct 14 | 167 | 5b |
| Lakewood | May 22 | Sep 28 | 129 | 4b |
| Lancaster | Apr 27 | Oct 11 | 166 | 5a |
| Laona | May 19 | Sep 29 | 131 | 4b |
| Lodi | May 1 | Oct 10 | 162 | 5a |
| Lone Rock Tri County Airport | Apr 30 | Oct 9 | 161 | 5a |
| Luck | May 6 | Oct 4 | 149 | 4b |
| Lynxville Dam | Apr 24 | Oct 17 | 175 | 5a |
| Madeline Island | May 20 | Oct 9 | 140 | 5a |
| Madison Dane Regional Airport | May 1 | Oct 10 | 160 | 5b |
| Manitowoc | Apr 30 | Oct 20 | 171 | 5b |
| Marinette | May 4 | Oct 11 | 160 | 5b |
| Markesan | May 8 | Oct 2 | 144 | 5a |
| Marshfield Experiment Farm | May 5 | Oct 5 | 150 | 4b |
| Marshfield Municipal Airport | May 5 | Oct 5 | 152 | 4b |
| Mather | May 6 | Oct 3 | 148 | 4b |
| Mauston | May 2 | Oct 7 | 158 | 5a |
| Mazomanie Wastewater Plant | May 7 | Oct 1 | 148 | 5a |
| Medford | May 11 | Oct 1 | 141 | 4a |
| Mellen | May 26 | Sep 27 | 125 | 4b |
| Menomonie | May 9 | Oct 1 | 143 | 4b |
| Merrill | May 11 | Sep 30 | 139 | 4b |
| Milwaukee Mitchell Airport | Apr 19 | Oct 29 | 192 | 6a |
| Minocqua | May 23 | Sep 27 | 127 | 4a |
| Minong | May 10 | Oct 4 | 144 | 4a |
| Mondovi | May 10 | Oct 2 | 144 | 4b |
| Monroe Wastewater Plant | Apr 27 | Oct 14 | 170 | 5a |
| Montello | May 3 | Oct 5 | 153 | 5a |
| Mount Mary College | Apr 26 | Oct 18 | 173 | 5b |
| Necedah | May 17 | Sep 25 | 131 | 4b |
| Necedah 5 mi WNW | May 1 | Oct 3 | 157 | 4b |
| Neillsville | May 10 | Oct 1 | 144 | 4b |
| New London | May 4 | Oct 6 | 153 | 5a |
| North Pelican | Jun 3 | Sep 18 | 106 | 4b |
| Oconomowoc Wastewater Plant | Apr 30 | Oct 12 | 164 | 5b |
| Oconto | May 9 | Oct 6 | 150 | 5a |
| Oshkosh | Apr 24 | Oct 20 | 178 | 5b |
| Oshkosh Wittman Airport | Apr 30 | Oct 13 | 165 | 5b |
| Owen | May 13 | Sep 26 | 136 | 4b |
| Paddock Lake | Apr 30 | Oct 15 | 167 | 5b |
| Park Falls Dnr Headquarters | May 15 | Sep 28 | 134 | 4a |
| Pattison Ranger Staion | May 18 | Oct 3 | 135 | 4b |
| Pell Lake | Apr 30 | Oct 13 | 164 | 5b |
| Peshtigo | May 11 | Oct 5 | 145 | 5b |
| Platteville | Apr 30 | Oct 13 | 166 | 5a |
| Plymouth Wastewater Plant | May 3 | Oct 10 | 159 | 5b |
| Port Washington | Apr 27 | Oct 22 | 176 | 5b |
| Port Wing | May 31 | Oct 2 | 123 | 5a |
| Portage Wastewater Plant | Apr 28 | Oct 10 | 164 | 5a |
| Prairie du Chien | Apr 28 | Oct 12 | 166 | 5a |
| Prentice | May 23 | Sep 23 | 124 | 4a |
| Racine | Apr 20 | Oct 24 | 184 | 6a |
| Racine Batten Airport | Apr 24 | Oct 24 | 180 | 6a |
| Reedsburg | May 2 | Oct 7 | 156 | 5a |
| Rest Lake | May 25 | Sep 21 | 117 | 4a |
| Rhinelander | May 22 | Sep 24 | 125 | 4b |
| Rhinelander 4 mi NE | May 23 | Sep 23 | 124 | 4b |
| Rhinelander Oneida Airport | May 26 | Sep 23 | 120 | 4b |
| Rice Lake | May 8 | Oct 2 | 145 | 4b |
| Rice Reservoir Tomahawk-2 | May 10 | Oct 4 | 146 | 4a |
| Richfield | Apr 30 | Oct 16 | 167 | 5a |
| Richland Center | May 5 | Oct 6 | 154 | 5a |
| Ridgeland | May 10 | Sep 29 | 140 | 4b |
| Ripon | May 1 | Oct 11 | 163 | 5a |
| River Falls | May 11 | Oct 1 | 143 | 4b |
| Rochester Wastewater Plant | May 5 | Oct 10 | 156 | 5b |
| Rock Springs | Apr 24 | Oct 20 | 178 | 5a |
| Rosholt | May 6 | Oct 5 | 150 | 4b |
| Sauk City Wastewater Plant | May 4 | Oct 6 | 155 | 5a |
| Saukville Wastewater Plant | May 5 | Oct 11 | 158 | 6a |
| Saxon | May 23 | Oct 1 | 132 | 4b |
| Shawano | May 9 | Oct 2 | 144 | 5a |
| Sheboygan | Apr 25 | Oct 23 | 179 | 6a |
| Sheboygan County Memorial Airport | May 5 | Oct 8 | 154 | 5b |
| Sheboygan Wastewater Plant | May 2 | Oct 21 | 169 | 6a |
| Slinger Wastewater Plant | May 5 | Oct 5 | 152 | 5a |
| Solon Springs | May 12 | Oct 2 | 142 | 4a |
| South Milwaukee Wastewater Plant | Apr 22 | Oct 26 | 184 | 6a |
| Sparta | May 9 | Oct 1 | 144 | 4b |
| Spooner Ag Res Station | May 14 | Sep 28 | 135 | 4a |
| St. Croix Falls | May 4 | Oct 8 | 156 | 4b |
| St. Germain | May 19 | Oct 3 | 136 | 4a |
| Stanley Wastewater Plant | May 7 | Oct 3 | 147 | 4b |
| Steuben | Apr 22 | Oct 20 | 179 | 5a |
| Stevens Point | May 4 | Oct 7 | 155 | 5a |
| Stockbridge-Munsee Rsvn | May 13 | Sep 30 | 141 | 4b |
| Stoughton | Apr 30 | Oct 11 | 163 | 5b |
| Sturgeon Bay Experiment Farm | May 8 | Oct 13 | 157 | 5b |
| Sullivan | May 3 | Oct 9 | 157 | 5b |
| Superior | May 6 | Oct 9 | 154 | 5a |
| Suring | May 14 | Oct 1 | 139 | 5a |
| Town of Westford | May 1 | Oct 11 | 163 | 5a |
| Trempealeau Dam | Apr 29 | Oct 11 | 165 | 5a |
| Two Rivers | Apr 27 | Oct 21 | 175 | 5b |
| Union Grove | May 5 | Oct 8 | 156 | 5b |
| Uw Arboretum - Madison | May 1 | Oct 9 | 161 | 5a |
| Viroqua | May 7 | Oct 2 | 148 | 5a |
| Washington Island | May 15 | Oct 14 | 152 | 6a |
| Waterloo Wastewater Plant | Apr 30 | Oct 9 | 163 | 5b |
| Watertown Wastewater Plant | Apr 28 | Oct 12 | 167 | 5b |
| Waukesha Wastewater Plant | May 1 | Oct 13 | 162 | 5b |
| Waupaca | May 8 | Oct 6 | 151 | 5a |
| Wausau Downtown Airport | May 6 | Oct 4 | 150 | 5a |
| West Allis | Apr 26 | Oct 22 | 177 | 5b |
| West Bend | May 4 | Oct 11 | 157 | 5b |
| West Bend Public Works | May 1 | Oct 12 | 161 | 5b |
| Weyerhaeuser | May 9 | Sep 29 | 140 | 4a |
| Whitewater | May 2 | Oct 9 | 157 | 5b |
| Willow Reservoir | May 13 | Oct 3 | 141 | 4a |
| Winter | May 19 | Sep 27 | 129 | 4a |
| Wisconsin Dells | May 8 | Oct 3 | 146 | 5a |
| Wisconsin Rapids | May 9 | Sep 30 | 142 | 4b |
| Wisconsin Rapids Alexander Field | May 8 | Oct 1 | 145 | 4b |
Median dates from NOAA 1991–2020 climate normals. How to read them.