Connecticut frost dates: C
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Canaan | May 11 | Oct 4 | 146 d | 6a |
| Canterbury | Apr 30 | Oct 15 | 168 d | 6b |
| Canton | Apr 25 | Oct 18 | 176 d | 6a |
| Canton Center | Apr 25 | Oct 18 | 176 d | 6a |
| Centerbrook | Apr 6 | Nov 17 | 225 d | 7a |
| Central Village | Apr 30 | Oct 15 | 168 d | 6b |
| Chaplin | Apr 19 | Oct 22 | 186 d | 6b |
| Cheshire | Apr 18 | Oct 26 | 191 d | 6b |
| Chester | Apr 26 | Oct 16 | 173 d | 6b |
| Clinton | Apr 6 | Nov 17 | 225 d | 7a |
| Cobalt | Apr 17 | Oct 26 | 192 d | 6b |
| Colchester | Apr 14 | Oct 24 | 193 d | 6b |
| Colebrook | May 3 | Oct 11 | 161 d | 6a |
| Collinsville | Apr 25 | Oct 18 | 176 d | 6a |
| Columbia | Apr 28 | Oct 13 | 168 d | 6b |
| Cornwall | May 11 | Oct 4 | 146 d | 6a |
| Cornwall Bridge | May 11 | Oct 4 | 146 d | 6a |
| Cos Cob | Apr 17 | Oct 23 | 189 d | 7a |
| Coventry | Apr 19 | Oct 22 | 186 d | 6b |
| Cromwell | Apr 17 | Oct 26 | 192 d | 6b |