The middle latitudes of the Northern Hemisphere have experienced fewer cold snaps during autumn and winter, thanks to Arctic warming.

Earlier studies have linked unusually frigid winters in North America and Europe over the past decade to changes in atmospheric circulation caused by rising Arctic temperatures. But when James Screen of the University of Exeter, UK, analysed global temperature data from 1979 to 2013, he found that the frequency and severity of autumn and winter cold extremes decreased during this period. In these seasons, the coldest days in the Northern Hemisphere's high and middle latitudes have warmed faster than the warmest days, reducing overall temperature variation. Climate models suggest that this trend will continue in the future.

The rapid warming of northerly winds, which carry cold Arctic air south, could be dampening winter extremes, Screen says.

Nature Clim. Change http://doi.org/s88 (2014)