Abstract

Several winters of the 2010s have brought to many midlatitude regions periods of extreme cold relative to the past few years and even decades. Further, it is suggested that melting of Arctic sea ice has increased the likelihood of persistent extreme weather conditions in the northern midlatitudes and the number of cold winter days. Here, estimates of warming in annual minimum temperature are updated and extended to all land areas where station temperature records are available, with emphasis on the midlatitudes. Annual minimum temperatures have warmed faster than mean temperatures in seasonally cold land regions and have already exceeded a 2 K warming threshold over the midlatitudes, but have warmed at about the same rate as mean temperatures in tropical climates. Recent regionally cold winters did not significantly deviate from the established warming trend and were within the range of interannual variability seen in the past. These findings have implications for contextualizing extreme winter weather, validating climate model projections of the consequences of sea ice loss, and guiding adaptation to shifting hardiness zones of perennial cultivars and the spread of pest and invasive species.