NOAA scientists said the average temperature for the contiguous 48 U.S. states during May was 64.3 degrees Fahrenheit, 3.3 degrees above the long-term average, making it the second warmest May on record.
The national average temperature for the March-May spring season was 57.1 degrees Fahrenheit, 5.2 degrees above the 1901-2000 long-term average, making it the warmest spring on record, a NOAA release said Friday.
That surpassed the previous warmest spring -- in 1910 -- by 2 degrees.
The high temperatures also contributed to the warmest year-to-date and the warmest 12-month period the nation has experienced since weather record-keeping began in 1895, NOAA said.
The warm temperatures brought mixed precipitation totals across the United States, with the nation as a whole being drier than average, researchers said.