Weather history and climate summary information is available for the following locations:
- Groton CT
- Hartford
- Stratford
- Windsor Locks
Warmest September Days
The warmest September days in Connecticut are:
| Windsor Locks, Connecticut | 1983 | 99°F |
| Windsor Locks, Connecticut | 2010 | 97°F |
| Windsor Locks, Connecticut | 1973 | 96.8°F |
| Hartford, Connecticut | 1983 | 96.1°F |
| Hartford, Connecticut | 2010 | 95°F |
Coldest September Days
The coldest September days in Connecticut were:
| Windsor Locks, Connecticut | 1978 | 29.8°F |
| Windsor Locks, Connecticut | 1979 | 29.8°F |
| Windsor Locks, Connecticut | 1974 | 30°F |
| Windsor Locks, Connecticut | 2000 | 30°F |
| Groton CT, Connecticut | 1991 | 30.2°F |
Wettest September Days
The wettest single days in September occurred:
| Windsor Locks, Connecticut | 2008 | 4.9 inches |
| Stratford, Connecticut | 2012 | 4.7 inches |
| Hartford, Connecticut | 1999 | 4.6 inches |
| Windsor Locks, Connecticut | 2003 | 4 inches |
| Windsor Locks, Connecticut | 2011 | 4 inches |