The autumn of 2016 was the warmest ever observed in records going back to 1895 for the 48 contiguous U.S. states, according to data released on Wednesday by NOAA’s National Centers for Environmental Information (NCEI). The nation’s average September-to-November temperature of 57.63°F was a full 1.05°F above the previous autumn record, set way back in 1963, and it was 4.08°F above the 20th-century average (see Figure 1). The record-setting margin of more than 1°F is a hefty one for a temperature record that spans an entire season and a landmass as large as the 48 contiguous states. For comparison, the second, third, fourth, fifth, sixth, and seventh-warmest U.S. autumns are all clustered within 1°F of each other, as are the six coldest autumns on record.
Pushing this past autumn to the top of the temperature pack were the third-warmest October and third-warmest November on record, along with the ninth-warmest September. Eight states along a swath from New Mexico to Michigan saw their warmest autumn on record, and every contiguous state except for California, Nevada, Oregon, and Washington had a top-ten warmest autumn (see Figure 2).