California frost dates: I
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Idyllwild | May 16 | Oct 24 | 161 d | 8a |
| Igo | Feb 13 | Dec 13 | 303 d | 9a |
| Imperial | Jan 4 | Dec 26 | 356 d | 10a |
| Imperial Beach | rare frost | 10b | ||
| Independence | Mar 31 | Nov 9 | 223 d | 8a |
| Indian Wells | Dec 31 | Dec 27 | 361 d | 10a |
| Indio | Dec 31 | Dec 27 | 361 d | 10a |
| Inglewood | rare frost | 10b | ||
| Inverness | Jan 1 | Dec 31 | 364 d | 10a |
| Inyokern | Mar 9 | Nov 20 | 256 d | 8b |
| Ione | Jan 22 | Dec 17 | 329 d | 9b |
| Irvine | Jan 5 | Dec 25 | 354 d | 10b |
| Isleton | Jan 12 | Dec 19 | 341 d | 9b |
| Ivanhoe | Jan 23 | Dec 13 | 324 d | 9b |