
Ocean surface temperature reached 20.96°C on July 30, according to the ERA5 database, while the previous record was 20.95°C in March 2016, a spokesman told AFP.
The samples tested excluded polar regions.
Oceans have absorbed 90% of the excess heat produced by human activity since the dawn of the industrial age, according to scientists.
Globally, the average ocean temperature has been besting seasonal heat records on a regular basis since April.
“The ocean heatwave is an immediate threat to some marine life. We are already seeing coral bleaching in Florida as a direct result and I expect more impacts will surface,” said Piers Forster of the International Centre for Climate at the University of Leeds.