May 2017 was the second hottest May ever recorded: NASA
May 2017 was the second warmest May in 137 years of record keeping, according to a monthly analysis of global temperatures by NASA. May 2016 was the hottest, being 0.05ÂºC warmer than this year's May and 0.93ÂºC warmer than the mean May temperature. The analysis was assembled from publicly available data acquired by about 6,300 meteorological stations around the world.