2016 is the warmest year on record to date, in large part because of a pronounced El Niño effect. 2015 and 2017 are tied for second, and 2018 currently holds the fourth position. But as WMO Secretary-General Petteri Taalas stresses, rankings are far less important than the overarching trend they illustrate. "And that trend," he cautions, "is an upward one." (Thumbnail image courtesy of Anurag Rana.)