Texas frost dates: O
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| O Brien | Mar 26 | Nov 11 | 230 d | 8a |
| Oakhurst | Mar 1 | Nov 28 | 272 d | 9a |
| Oakland | Feb 17 | Dec 4 | 290 d | 9a |
| Oakville | Feb 8 | Dec 6 | 301 d | 9b |
| Oakwood | Mar 12 | Nov 19 | 252 d | 8b |
| Odell | Mar 27 | Nov 9 | 227 d | 7b |
| Odem | Feb 1 | Dec 17 | 319 d | 9b |
| Odessa | Mar 15 | Nov 16 | 246 d | 8b |
| Odonnell | Apr 2 | Nov 8 | 220 d | 8a |
| Oglesby | Mar 15 | Nov 18 | 248 d | 8b |
| Oilton | Jan 30 | Dec 18 | 322 d | 9b |
| Oklaunion | Mar 27 | Nov 9 | 227 d | 8a |
| Old Glory | Mar 29 | Nov 7 | 223 d | 8a |
| Old Ocean | Feb 20 | Dec 3 | 286 d | 9b |
| Olden | Mar 30 | Nov 4 | 219 d | 8a |
| Olmito | Jan 9 | Jan 4 | 360 d | 10a |
| Olney | Mar 31 | Nov 8 | 222 d | 8a |
| Olton | Apr 6 | Nov 1 | 209 d | 7a |
| Omaha | Mar 24 | Nov 7 | 228 d | 8b |
| Onalaska | Mar 1 | Nov 24 | 268 d | 9a |
| Orange | Feb 28 | Nov 23 | 268 d | 9a |
| Orange Grove | Jan 31 | Dec 23 | 326 d | 9b |
| Orangefield | Feb 14 | Dec 7 | 296 d | 9b |
| Orchard | Feb 28 | Nov 30 | 275 d | 9a |
| Ore City | Mar 10 | Nov 15 | 250 d | 8b |
| Orla | Apr 4 | Nov 6 | 216 d | 8a |
| Ottine | Mar 5 | Nov 23 | 263 d | 9a |
| Ovalo | Apr 3 | Nov 4 | 215 d | 8a |
| Overton | Mar 15 | Nov 16 | 246 d | 8b |
| Ozona | Mar 21 | Nov 6 | 230 d | 8a |