In May, the combined land and ocean surface temperature was 1.57 degrees (F) above the 20th-century average, 0.14 degrees above the previous record set last year (May 2014).
Fueled by the strengthening El Niño event, May’s ocean temperatures were particularly warm. “Notably, record warmth was observed across much of the equatorial Pacific as well as parts of the equatorial and southern Indian Ocean and the Barents Sea to the north of Scandinavia,” NOAA’s report said.
Over land areas, record warmth occurred in most of Alaska, parts of tropical South America, much of southern Africa and the Middle East, and parts of northwestern Siberia, NOAA said.
Pockets of cooler-than-normal conditions were observed in Iceland, Greenland, the United Kingdom and Norway as well as the central United States, which had its wettest May on record.
NOAA joins the Japan Meteorological Agency in finding it was the warmest May on record. However, NASA’s analysis of global temperatures determined it tied for second warmest.
Satellite measurements of lower tropospheric temperatures (the layer just above the Earth’s surface) maintained by the University of Alabama at Huntsville found it was the third warmest May in its 38-year record.
With a strengthening El Niño event underway, it is very likely upcoming months will rank as or near the warmest on record and that 2015 will move ahead of 2014 as the warmest year on record once the year is complete.
“If an ENSO [El Niño Southern Oscillation] event is strong and long-lived, it will leave an unmistakable mark on the global temperature,” wrote NOAA’s Deke Arndt at Climate.gov.