According to WeatherForYou.com:
1861 - The temperature at Gouverneur, NY, bottomed out at -40 degrees, a drop of 70 degrees in one day. Two days later the mercury hit 55 degrees.
1978 - The worst winter storm of record struck coastal New England. The storm produced 27.5 inches of snow at Boston, and nearly 50 inches in northeastern Rhode Island. The fourteen foot tide at Portland ME was probably the highest of the century. Winds gusted to 79 mph at Boston, and reached 92 mph at Chatham MA. A hurricane size surf caused 75 deaths and 500 million dollars damage.
Miami- RECORD HIGH: 87° in 2003
RECORD LOW: 40° in 1978
Fort Lauderdale- RECORD HIGH: 88° in 1949
RECORD LOW: 39° in 1978
Key West- RECORD HIGH: 84° in 1949
RECORD LOW: 48° IN 1978