New Hampshire frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Barnstead | May 8 | Oct 3 | 148 d | 5b |
| Barrington | May 3 | Oct 10 | 160 d | 6a |
| Bartlett | May 7 | Oct 5 | 151 d | 5a |
| Bath | May 15 | Sep 28 | 136 d | 5a |
| Bedford | Apr 21 | Oct 19 | 181 d | 6a |
| Belmont | Apr 30 | Oct 18 | 171 d | 5b |
| Bennington | May 9 | Oct 5 | 149 d | 5b |
| Berlin | May 14 | Sep 30 | 139 d | 4b |
| Bethlehem | May 24 | Sep 18 | 117 d | 5a |
| Bow | May 8 | Oct 3 | 148 d | 6a |
| Bradford | May 15 | Sep 27 | 135 d | 5b |
| Bretton Woods | frost any month | 5a | ||
| Bristol | May 21 | Sep 26 | 128 d | 5b |
| Brookline | Apr 28 | Oct 8 | 163 d | 6a |