Maryland frost dates: H
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Hagerstown | Apr 11 | Oct 28 | 200 d | 7a |
| Halethorpe | Apr 10 | Oct 31 | 204 d | 7b |
| Hampstead | Apr 19 | Oct 25 | 189 d | 7a |
| Hancock | Apr 23 | Oct 21 | 181 d | 7a |
| Hanover | Apr 10 | Oct 31 | 204 d | 7b |
| Harmans | Apr 10 | Oct 31 | 204 d | 7b |
| Harwood | Apr 9 | Oct 29 | 203 d | 7b |
| Havre De Grace | Apr 10 | Oct 30 | 203 d | 7b |
| Hebron | Apr 2 | Nov 10 | 222 d | 7b |
| Helen | Mar 22 | Nov 26 | 249 d | 7b |
| Henderson | Apr 4 | Nov 4 | 214 d | 7b |
| Highland | Apr 5 | Nov 9 | 218 d | 7b |
| Hillsboro | Apr 1 | Nov 7 | 220 d | 7b |
| Hollywood | Mar 22 | Nov 26 | 249 d | 7b |
| Hughesville | Apr 17 | Oct 27 | 193 d | 7b |
| Hunt Valley | Apr 2 | Nov 7 | 219 d | 7b |
| Huntingtown | Apr 17 | Oct 27 | 193 d | 7b |
| Hurlock | Apr 8 | Nov 4 | 210 d | 7b |
| Hyattsville | Mar 29 | Nov 8 | 224 d | 7b |
| Hydes | Apr 2 | Nov 7 | 219 d | 7b |