Weather history and climate summary information is available for the following locations:
- Washington
Warmest September Days
The warmest September days in District of Columbia are:
| Washington, District of Columbia | 1953 | 101.3°F |
| Washington, District of Columbia | 1980 | 100.9°F |
| Washington, District of Columbia | 1954 | 100.2°F |
| Washington, District of Columbia | 1939 | 100.2°F |
| Washington, District of Columbia | 2010 | 99°F |
Coldest September Days
The coldest September days in District of Columbia were:
| Washington, District of Columbia | 1940 | 39.4°F |
| Washington, District of Columbia | 1942 | 39.9°F |
| Washington, District of Columbia | 1947 | 40.3°F |
| Washington, District of Columbia | 1963 | 43.3°F |
| Washington, District of Columbia | 1956 | 44.4°F |
Wettest September Days
The wettest single days in September occurred:
| Washington, District of Columbia | 1985 | 4 inches |
| Washington, District of Columbia | 2008 | 3.5 inches |
| Washington, District of Columbia | 1976 | 3.4 inches |
| Washington, District of Columbia | 1975 | 3.2 inches |
| Washington, District of Columbia | 1979 | 3.1 inches |