Wisconsin frost dates: M
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Madison | May 1 | Oct 9 | 161 d | 5b |
| Maiden Rock | May 13 | Sep 29 | 139 d | 4b |
| Malone | May 1 | Oct 12 | 164 d | 5b |
| Manawa | May 8 | Oct 6 | 151 d | 5a |
| Manitowish Waters | May 25 | Sep 21 | 119 d | 4a |
| Manitowoc | Apr 30 | Oct 20 | 173 d | 5b |
| Maple | May 24 | Sep 26 | 125 d | 4b |
| Maplewood | May 6 | Oct 17 | 164 d | 5b |
| Marathon | May 6 | Oct 4 | 151 d | 4b |
| Marengo | May 26 | Sep 27 | 124 d | 4b |
| Maribel | May 6 | Oct 12 | 159 d | 5b |
| Marinette | May 4 | Oct 11 | 160 d | 5b |
| Marion | May 4 | Oct 6 | 155 d | 5a |
| Markesan | May 8 | Oct 2 | 147 d | 5a |
| Marquette | May 6 | Oct 2 | 149 d | 5a |
| Marshall | Apr 30 | Oct 9 | 162 d | 5b |
| Marshfield | May 5 | Oct 5 | 153 d | 4b |
| Mason | May 20 | Oct 1 | 134 d | 4b |
| Mather | May 6 | Oct 3 | 150 d | |
| Mattoon | May 14 | Sep 30 | 139 d | 4b |
| Mauston | May 2 | Oct 7 | 158 d | 5a |
| Mayville | May 1 | Oct 10 | 162 d | 5a |
| Mazomanie | May 7 | Oct 1 | 147 d | 5a |
| Mc Farland | May 1 | Oct 9 | 161 d | 5b |
| Mc Naughton | May 26 | Sep 23 | 120 d | 4b |
| Medford | May 11 | Oct 1 | 143 d | 4a |
| Mellen | May 26 | Sep 27 | 124 d | 4a |
| Melrose | May 9 | Oct 1 | 145 d | 4b |
| Menasha | May 4 | Oct 6 | 155 d | 5b |
| Menomonee Falls | May 6 | Oct 8 | 155 d | 5b |
| Menomonie | May 9 | Oct 1 | 145 d | 4b |
| Mequon | Apr 23 | Oct 24 | 184 d | 5b |
| Mercer | May 25 | Sep 21 | 119 d | 4a |
| Merrill | May 11 | Sep 30 | 142 d | 4b |
| Merrillan | May 10 | Oct 1 | 144 d | 4b |
| Merrimac | May 1 | Oct 10 | 162 d | 5a |
| Merton | Apr 30 | Oct 16 | 169 d | 5b |
| Middleton | Apr 28 | Oct 15 | 170 d | 5a |
| Mikana | May 9 | Sep 29 | 143 d | 4a |
| Milladore | May 5 | Oct 5 | 153 d | 4b |
| Millston | May 6 | Oct 3 | 150 d | 4b |
| Milltown | May 6 | Oct 4 | 151 d | 4b |
| Milton | Apr 28 | Oct 13 | 168 d | 5b |
| Milwaukee | Apr 26 | Oct 22 | 179 d | 6a |
| Mindoro | May 9 | Oct 1 | 145 d | 4b |
| Mineral Point | May 3 | Oct 7 | 157 d | 5a |
| Minocqua | May 23 | Sep 27 | 127 d | 4a |
| Minong | May 10 | Oct 4 | 147 d | 4a |
| Mishicot | Apr 27 | Oct 21 | 177 d | 5b |
| Mondovi | May 10 | Oct 2 | 145 d | 4b |
| Monroe | Apr 27 | Oct 14 | 170 d | 5a |
| Montello | May 3 | Oct 5 | 155 d | 5a |
| Montfort | Apr 30 | Oct 13 | 166 d | 5a |
| Monticello | Apr 27 | Oct 14 | 170 d | 5a |
| Montreal | May 24 | Sep 28 | 127 d | 4a |
| Morrisonville | May 4 | Oct 6 | 155 d | 5a |
| Mosinee | May 6 | Oct 4 | 151 d | 5a |
| Mount Calvary | May 1 | Oct 12 | 164 d | 5b |
| Mount Hope | Apr 27 | Oct 11 | 167 d | 5a |
| Mount Horeb | May 7 | Oct 1 | 147 d | 5a |
| Mount Sterling | May 3 | Oct 7 | 157 d | 5a |
| Mountain | May 22 | Sep 28 | 129 d | 4b |
| Mukwonago | May 1 | Oct 13 | 165 d | 5b |
| Muscoda | May 5 | Oct 6 | 154 d | 5a |
| Muskego | May 3 | Oct 14 | 164 d | 5b |