AMHERST – Official observers reported this week that all the Northeast states just saw their warmest December on record, with average air temperatures in each more than 13 degrees F above normal for the month. Records for the Northeast and lower 48 states go back 121 years to 1895, says Michael Rawlins, assistant professor and manager of the Climate System Research Center at the University of Massachusetts Amherst.
Representative organizations in the United States, Britain and Japan are expected to soon announce that globally, 2015 was the warmest year on record, as well, he adds. In the U.S., 2015 saw some 10,000 warm records set, 20 times the number of cold records. “This skewed ratio, common in recent years, is a hallmark of a warming climate,” Rawlins says.
For New England, last month may have been the warmest December over at least the past 180 years, with Hartford, Worcester, Boston, Providence, Concord, Burlington and Albany all expected to post their warmest December on record.
In Amherst, National Weather Service observations during December show an average of 40.4 degrees, 11.5 degrees above normal and warmer by 3.5 degrees than the prior warmest December for the area in 1891. Observations here began in 1835, making the instrumental record one of the longest in the U.S., Rawlins notes.
For 2015 as a whole, temperatures across the Northeast were near or slightly above normal, despite notable cold over the first three months, particularly last February, he points out. After that, it was warmer than average from September through December. Fall 2015, from September through November, ranked second to fourth warmest at most Northeast reporting stations. Hartford was typical, with its coldest month on record last February and its warmest month on record in both May and December.
From 1912 to 2011, Decembers in Massachusetts have warmed by approximately 2.8 degrees (0.28 degrees per decade), Rawlins says. Since 1836, December temperatures in Amherst have warmed by some 5 degrees. An analysis by Climate Central found that since 1912, states with average winter temperatures below 32 degrees warmed three times faster than states with average temperatures above 32 degrees.
As for precipitation, the year 2015 was the third wettest year on record for the contiguous United States. Boston had its snowiest month ever in February, its snowiest winter and snowiest season from 1872 to the present. Annual precipitation averaged across the Northeast was near normal, 42.52 inches, within one-half inch of the 20th century average. However, Connecticut had its fourth driest year on record.
