Via the Illinois State Climatologist, NOAA reported this week that 2015 was extraordinarily warm:
The 2015 annual average U.S. temperature was 12.4°C, 1.3°C above the 20th century average, the second warmest year on record. Only 2012 was warmer for the U.S. with an average temperature of 12.9°C. This is the 19th consecutive year the annual average temperature exceeded the 20th century average.
Moreover, in 2015, every part of the lower 48 states had above-average temperatures:
Nineteen consecutive years of above-average temperatures. Yes, that does mean they'll change the averages soon. But they've already done once in the past 19 years, since normal temperatures are based on moving 30-year data sets. (Current normals are based on the period 1981-2010.)