2012 didn’t just set the record for warmest year on record in the contiguous United States, it blew the old one out of the water. NOAA has confirmed that every state in the lower-48 experienced a warmer than normal year. 19 states had a record warm year.
The year started with an unseasonably mild, and relatively snow-free, winter throughout most of the country. Spring was even warmer (relative to normal) and the growing season started early, leading to an increased demand for water. The lack of snowmelt exacerbated the situation, and a large chunk of the country slipped into a drought in the summer. The drought persisted into the fall, and by late-November 62.7% of the contiguous U.S. was experiencing moderate to exceptional drought conditions.
The very warm weather continued into, and peaked during, the summer. July was the hottest month on record in the lower-48, with an average temperature of 76.9° F, 3.6° F above normal. June and August were also warmer than normal nationwide, and the summer as a whole was the second warmest on record.
2012 was the warmest yr in the US on record by a wide margin. See images & animation of #2012 annual & monthly temps: http://t.co/YJHGXecl
— NOAA Climate.gov (@NOAAClimate) January 8, 2013
The temperature remained above normal through the fall, but not to the degree that was experienced earlier in the year. It was still enough, however, for 2012 to easily eclipse 1998 as the warmest year on record. The average temperature for the contiguous United States was 55.3° F, which was 3.2° F above the twentieth-century average and 1.0° F warmer than 1998.
2012 also had its fair share of individual extreme weather events. Among them, Superstorm Sandy, Hurricane Isaac, the Derecho that blew through the Mid-Atlantic this summer, and significant wildfires in the West.
Locally, after further review, NOAA has moved 2012 from the second warmest year on record in Providence to the warmest year on record. It was also the warmest year on record in Boston and New York.