New Jersey frost dates: O
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Oak Ridge | Apr 25 | Oct 17 | 175 d | 6b |
| Oakhurst | Apr 9 | Nov 3 | 208 d | 7b |
| Oakland | Apr 19 | Oct 23 | 187 d | 7a |
| Oaklyn | Apr 15 | Oct 31 | 199 d | 7b |
| Ocean City | Mar 26 | Nov 22 | 241 d | 7b |
| Ocean Gate | Apr 23 | Oct 20 | 180 d | 7b |
| Ocean Grove | Apr 9 | Nov 3 | 208 d | 7b |
| Ocean View | Apr 24 | Oct 22 | 181 d | 7b |
| Oceanport | Apr 9 | Nov 3 | 208 d | 7b |
| Oceanville | Apr 18 | Oct 29 | 194 d | 7b |
| Ogdensburg | Apr 24 | Oct 16 | 175 d | 6b |
| Old Bridge | Apr 17 | Oct 23 | 189 d | 7a |
| Oldwick | Apr 26 | Oct 18 | 175 d | 7a |
| Oradell | Apr 3 | Nov 4 | 215 d | 7a |
| Orange | Apr 18 | Oct 24 | 189 d | 7a |
| Oxford | Apr 30 | Oct 18 | 171 d | 6b |