Maine frost dates: R
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Randolph | May 1 | Oct 11 | 163 d | 5b |
| Rangeley | May 23 | Sep 27 | 127 d | 4b |
| Raymond | Apr 30 | Oct 20 | 173 d | 5b |
| Readfield | Apr 27 | Oct 16 | 172 d | 5b |
| Richmond | May 1 | Oct 11 | 163 d | 5b |
| Robbinston | May 5 | Oct 13 | 161 d | 5b |
| Rockland | Apr 27 | Oct 19 | 175 d | 6a |
| Rockport | Apr 27 | Oct 19 | 175 d | 6a |
| Rockwood | May 21 | Sep 21 | 123 d | 4b |
| Round Pond | Apr 27 | Oct 18 | 174 d | 6a |
| Roxbury | May 19 | Sep 25 | 129 d | 5a |
| Rumford | May 4 | Oct 6 | 155 d | 5a |