The average temperature for 2012 was 55.3 F (12.9 C), which is 3.2 F above the 20th century average, and 1.0 F above 1998, the previous warmest year. | iStockphoto

2012 Warmest on Record for U.S.

The United States saw record weather extremes in 2012 and the highest average temperature in history.

January 9, 2013
3:00 AM EST