Oklahoma frost dates: H
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Haileyville | Mar 31 | Nov 3 | 217 d | 7b |
| Hallett | Apr 6 | Oct 29 | 206 d | 7a |
| Hammon | Apr 16 | Oct 23 | 190 d | 7a |
| Hanna | Mar 31 | Nov 3 | 217 d | 7b |
| Hardesty | Apr 16 | Oct 25 | 192 d | 6b |
| Harrah | Apr 2 | Nov 5 | 217 d | 7b |
| Hartshorne | Mar 31 | Nov 3 | 217 d | 7b |
| Haskell | Apr 1 | Nov 1 | 214 d | 7b |
| Hastings | Mar 24 | Nov 8 | 229 d | 8a |
| Haworth | Mar 31 | Nov 3 | 217 d | 8a |
| Headrick | Apr 5 | Nov 2 | 211 d | 7b |
| Healdton | Apr 6 | Nov 1 | 209 d | 8a |
| Heavener | Apr 6 | Nov 2 | 210 d | 7b |
| Helena | Apr 9 | Oct 31 | 205 d | 7a |
| Hendrix | Mar 19 | Nov 12 | 238 d | 8a |
| Hennepin | Apr 6 | Nov 1 | 209 d | 8a |
| Hennessey | Apr 14 | Oct 30 | 199 d | 7a |
| Henryetta | Apr 8 | Oct 28 | 203 d | 7b |
| Hillsdale | Apr 6 | Nov 1 | 209 d | 7a |
| Hinton | Apr 5 | Nov 1 | 210 d | 7b |
| Hitchcock | Apr 14 | Oct 27 | 196 d | 7a |
| Hitchita | Apr 8 | Oct 28 | 203 d | 7b |
| Hobart | Apr 7 | Nov 4 | 211 d | 7b |
| Hodgen | Apr 6 | Nov 2 | 210 d | 7b |
| Holdenville | Mar 29 | Nov 5 | 221 d | 7b |
| Hollis | Apr 5 | Oct 31 | 209 d | 7b |
| Hollister | Mar 26 | Nov 10 | 229 d | 8a |
| Hominy | Mar 31 | Oct 31 | 214 d | 7a |
| Honobia | Apr 13 | Oct 27 | 197 d | 7b |
| Hooker | Apr 16 | Oct 25 | 192 d | 6b |
| Hopeton | Apr 11 | Oct 26 | 198 d | 7a |
| Howe | Apr 6 | Nov 2 | 210 d | 7b |
| Hoyt | Apr 6 | Oct 30 | 207 d | 7b |
| Hugo | Mar 15 | Nov 15 | 245 d | 8a |
| Hulbert | Apr 4 | Oct 31 | 210 d | 7b |
| Hunter | Apr 18 | Oct 20 | 185 d | 7a |
| Hydro | Apr 5 | Nov 1 | 210 d | 7b |