Mississippi frost dates: O
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Oak Vale | Mar 12 | Nov 10 | 243 d | 8b |
| Oakland | Apr 1 | Nov 3 | 216 d | 8a |
| Ocean Springs | Feb 12 | Dec 14 | 305 d | 9a |
| Okolona | Mar 21 | Nov 9 | 233 d | 8a |
| Olive Branch | Mar 26 | Nov 6 | 225 d | 8a |
| Osyka | Mar 11 | Nov 18 | 252 d | 8b |
| Ovett | Mar 12 | Nov 12 | 245 d | 8b |
| Oxford | Apr 3 | Oct 31 | 211 d | 8a |