According to a latest analysis from NOAA's National Climatic Data Center United States is currently experiencing its warmest spring (March-May) on record, with national average temperature being 57.1°F, 5.2°F above the 1901-2000 long-term average, overtaking the previous warmest spring (1910) by 2.0°F.
In fact, this May was the second warmest May on record, with the average national temperature being 64.3°F, surpassing the long-term average by 3.3°F.
Other interesting findings include:
Twenty-six states had May temperatures ranking among their ten warmest. Only Oregon and Washington had spring temperatures (March-May) near normal.
Midwest were wetter than average and the Northwest was the only area that hasn't experienced warmer than average temperatures.
Ongoing drought, combined with windy conditions, created ideal wildfire conditions across the Southwest, and led to largest wildfire on record for the state of New Mexico.
37.4 percent of the contiguous U.S. experienced drought conditions at the end of the May.
This year's spring had warmest March, third warmest April and second warmest May on record.
The June 2011-May 2012 period was the warmest 12-month period on record for the contiguous United States.
The more info with even more data can be found here http://www.ncdc.noaa.gov/sotc/national/2012/5.