2012 was warmest and second most extreme year on record for the contiguous U.S.

2012 was a historic year for extreme weather that included drought, wildfires, hurricanes and storms; however, tornado activity was below average, according to an analysis released today by NOAA's National Climatic Data Center. The average temperature for 2012 was 55.3°F, 3.2°F above the 20th century average, and 1.0°F above 1998, the previous warmest year.

http://www.ncdc.noaa.gov/sotc