May temperature differences from normal. (NOAA)

NOAA announced today that Earth just had its warmest May on record, extending its warmest start to a calendar year in recorded history.

Every month in 2015 so far has ranked among the top four warmest for the globe. May and March were the warmest on record, January and February were the second warmest on record, and April was the fourth warmest on record.

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.

[Weather Service joins call for a strong El Niño event]

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.

[Alaska just had its hottest May in 91 years]

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.

[May was the wettest month for U.S. in 121 years of record-keeping]

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.


Time series of May global temperatures with respect to normal. (Japan Meteorological Agency)

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.


Via NOAA: “Monthly temperature from 1982-April 2015 compared to the 1901-2000 average, with El Niño-flavored months in red, La Niña-flavored months in blue, and neutral months in gray. Graphic by Deke Arndt and Climate.gov”

“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.