Virginia frost dates: O
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Oak Hall | Mar 31 | Nov 11 | 225 d | 8a |
| Oakpark | Apr 7 | Oct 30 | 206 d | 7a |
| Oakton | Apr 14 | Oct 29 | 198 d | 7b |
| Oakwood | Apr 21 | Oct 26 | 188 d | 7a |
| Occoquan | Mar 28 | Nov 8 | 225 d | 7b |
| Oilville | Apr 17 | Oct 27 | 193 d | 7a |
| Oldhams | Apr 8 | Oct 30 | 205 d | 7b |
| Onancock | Apr 4 | Nov 7 | 217 d | 8a |
| Onemo | Apr 1 | Nov 10 | 223 d | 8a |
| Onley | Apr 4 | Nov 7 | 217 d | 8a |
| Ophelia | Mar 30 | Nov 14 | 229 d | 8a |
| Orange | Apr 7 | Oct 30 | 206 d | 7a |
| Ordinary | Apr 1 | Nov 10 | 223 d | 8a |
| Oriskany | Apr 27 | Oct 18 | 174 d | 7b |
| Orkney Springs | May 3 | Oct 12 | 162 d | 6b |
| Orlean | Apr 9 | Nov 1 | 206 d | 7a |
| Oyster | Mar 28 | Nov 17 | 234 d | 8a |