Wisconsin frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Babcock | May 8 | Oct 1 | 146 d | 4b |
| Bagley | Apr 21 | Oct 18 | 180 d | 5a |
| Baileys Harbor | May 14 | Oct 18 | 157 d | 5b |
| Baldwin | May 6 | Oct 2 | 149 d | 4b |
| Balsam Lake | May 6 | Oct 4 | 151 d | 4b |
| Bancroft | May 10 | Oct 3 | 146 d | 4b |
| Bangor | May 9 | Oct 1 | 145 d | 4b |
| Baraboo | May 5 | Oct 5 | 153 d | 5a |
| Barneveld | May 3 | Oct 7 | 157 d | 5a |
| Barron | May 8 | Oct 2 | 147 d | 4b |
| Barronett | May 5 | Oct 4 | 152 d | 4b |
| Bassett | Apr 30 | Oct 13 | 166 d | 5b |
| Bay City | May 13 | Sep 29 | 139 d | 4b |
| Bayfield | May 20 | Oct 8 | 141 d | 5a |
| Bear Creek | May 4 | Oct 6 | 155 d | 5a |
| Beaver Dam | May 2 | Oct 9 | 160 d | 5a |
| Beetown | Apr 27 | Oct 11 | 167 d | 5a |
| Beldenville | May 13 | Sep 29 | 139 d | 4b |
| Belgium | May 5 | Oct 12 | 160 d | 5b |
| Belleville | May 1 | Oct 9 | 161 d | 5a |
| Belmont | Apr 30 | Oct 13 | 166 d | 5a |
| Beloit | May 1 | Oct 12 | 164 d | 5b |
| Benet Lake | Apr 23 | Oct 21 | 181 d | 5b |
| Benoit | May 23 | Sep 29 | 129 d | 4b |
| Benton | Apr 26 | Oct 15 | 172 d | 5a |
| Berlin | May 1 | Oct 8 | 160 d | 5a |
| Big Bend | May 1 | Oct 13 | 165 d | 5b |
| Big Falls | May 4 | Oct 6 | 155 d | 5a |
| Birchwood | frost any month | 4a | ||
| Birnamwood | May 6 | Oct 5 | 152 d | 4b |
| Black Creek | May 4 | Oct 6 | 155 d | 5a |
| Black Earth | May 7 | Oct 1 | 147 d | 5a |
| Black River Falls | May 9 | Oct 1 | 145 d | 4b |
| Blair | May 9 | Oct 1 | 145 d | 4b |
| Blanchardville | May 3 | Oct 4 | 154 d | 5a |
| Blenker | May 5 | Oct 5 | 153 d | 4b |
| Bloomer | May 5 | Oct 3 | 151 d | 4b |
| Bloomington | Apr 27 | Oct 11 | 167 d | 5a |
| Blue Mounds | May 7 | Oct 1 | 147 d | 5a |
| Blue River | May 3 | Oct 7 | 157 d | 5a |
| Bonduel | May 9 | Oct 2 | 146 d | 5a |
| Boscobel | May 3 | Oct 7 | 157 d | 5a |
| Boulder Junction | May 25 | Sep 21 | 119 d | 4a |
| Bowler | May 13 | Sep 30 | 140 d | 4b |
| Boyceville | May 10 | Sep 29 | 142 d | 4b |
| Boyd | May 7 | Oct 3 | 149 d | 4b |
| Brandon | May 8 | Oct 2 | 147 d | 5a |
| Brantwood | May 23 | Sep 23 | 123 d | 4a |
| Briggsville | May 8 | Oct 3 | 148 d | 5a |
| Brill | May 8 | Oct 2 | 147 d | 4a |
| Brillion | May 6 | Oct 6 | 153 d | 5b |
| Bristol | Apr 30 | Oct 15 | 168 d | 5b |
| Brodhead | Apr 29 | Oct 12 | 166 d | 5a |
| Brokaw | May 6 | Oct 4 | 151 d | 4b |
| Brookfield | Apr 30 | Oct 14 | 167 d | 5b |
| Brooklyn | Apr 30 | Oct 11 | 164 d | 5b |
| Brownsville | Apr 27 | Oct 19 | 175 d | 5a |
| Browntown | Apr 27 | Oct 14 | 170 d | 5a |
| Bruce | May 9 | Sep 29 | 143 d | 4b |
| Brule | May 24 | Sep 26 | 125 d | 4a |
| Brussels | May 6 | Oct 17 | 164 d | 5b |
| Bryant | May 14 | Sep 30 | 139 d | 4b |
| Burlington | May 5 | Oct 9 | 157 d | 5b |
| Burnett | May 1 | Oct 10 | 162 d | 5a |
| Butler | Apr 26 | Oct 18 | 175 d | 5b |
| Butte Des Morts | Apr 24 | Oct 20 | 179 d | 5b |
| Butternut | May 22 | Sep 24 | 125 d | 4a |