How unusual was the cold winter of 2013/14 in the upper midwest? Bulletin of the American Meteorological Society

Below-normal temperatures covered the Upper Midwest and Great Lakes region from November 2013 through April 2014, the longest such consecutive monthly stretch since 1995–96, culminating in the coldest winter since 1978/79.1 The U.S. economy suffered a severe setback,2 in part due to the harsh winter (Boldin and Wright 2015; Bloesch and Gourio 2015). Direct economic losses due to wintry weather totaled at least $4 billion (U.S. dollars).3 The largest Great Lakes ice extent since 19794 hindered shipping exceptionally long into spring.5 The frigid weather after two decades of mostly mild winters surprised many, who were not warned by seasonal forecasts either (see Supplemental Figs. S3.1, S3.2).