Temperature on land set a heat record, while ocean temperatures ranked second.
Parts of Africa, Asia, western Europe, South and Central America had record warmth.
“We continue to warm on the long term and in any given month we’re likely to be knocking on the door, close to a record in the era that we’re in,” NOAA climate monitoring chief Deke Arndt said.
The last seven Mays, from 2014 to 2020, have been the seven warmest Mays on record.
This past spring was the second hottest on record, behind 2016. And this year so far is the second hottest five-month start of a year.
Arndt said it’s highly likely that 2020 will be one of the two hottest years since 1880.