Weather history and climate summary information is available for the following locations:
- Groton CT
- Hartford
- Stratford
- Windsor Locks
Warmest December Days
The warmest December days in Connecticut are:
| Windsor Locks, Connecticut | 1998 | 75.9°F |
| Hartford, Connecticut | 1998 | 75.2°F |
| Windsor Locks, Connecticut | 1984 | 73.9°F |
| Windsor Locks, Connecticut | 2001 | 73.9°F |
| Stratford, Connecticut | 1998 | 73.4°F |
Coldest December Days
The coldest December days in Connecticut were:
| Windsor Locks, Connecticut | 1980 | -14.1°F |
| Windsor Locks, Connecticut | 1942 | -10.7°F |
| Windsor Locks, Connecticut | 1989 | -9.2°F |
| Stratford, Connecticut | 1942 | -6.5°F |
| Windsor Locks, Connecticut | 1975 | -6°F |
Wettest December Days
The wettest single days in December occurred:
| Hartford, Connecticut | 2008 | 3.5 inches |
| Stratford, Connecticut | 2008 | 3.4 inches |
| Windsor Locks, Connecticut | 2010 | 3.3 inches |
| Windsor Locks, Connecticut | 2008 | 3.3 inches |
| Groton CT, Connecticut | 2008 | 3.2 inches |