Oklahoma frost dates: R
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Ralston | Apr 11 | Oct 24 | 196 d | 7a |
| Ramona | Apr 11 | Oct 24 | 196 d | 7a |
| Randlett | Mar 26 | Nov 9 | 228 d | 8a |
| Ratliff City | Mar 28 | Nov 7 | 224 d | 8a |
| Rattan | Apr 3 | Nov 1 | 212 d | 8a |
| Ravia | Mar 29 | Nov 5 | 221 d | 8a |
| Red Oak | Apr 2 | Nov 5 | 217 d | 7b |
| Red Rock | Apr 8 | Oct 28 | 203 d | 7a |
| Redbird | Mar 29 | Nov 5 | 221 d | 7b |
| Rentiesville | Apr 2 | Nov 2 | 214 d | 7b |
| Reydon | Apr 3 | Nov 3 | 214 d | 7a |
| Ringling | Mar 23 | Nov 7 | 229 d | 8a |
| Ringold | Apr 13 | Oct 27 | 197 d | 8a |
| Ringwood | Apr 10 | Oct 31 | 204 d | 7a |
| Ripley | Apr 1 | Nov 5 | 218 d | 7a |
| Rocky | Apr 5 | Nov 4 | 213 d | 7b |
| Roff | Apr 4 | Nov 1 | 211 d | 7b |
| Roland | Mar 25 | Nov 6 | 226 d | 8a |
| Roosevelt | Apr 4 | Nov 4 | 214 d | 7b |
| Rose | Mar 31 | Nov 2 | 216 d | 7a |
| Rosston | Apr 13 | Oct 28 | 198 d | 7a |
| Rufe | Mar 31 | Nov 3 | 217 d | 8a |
| Rush Springs | Apr 4 | Oct 31 | 210 d | 7b |
| Ryan | Mar 29 | Nov 5 | 221 d | 8a |