From ZME Science:
On August 22, the average surface temperature of the planet’s extra-polar oceans hit 21.1°C (70°F), the highest daily level in recorded modern history.
The timing makes the record especially concerning. This is because global ocean temperatures typically reach their peak around March and April. However, this new high arrived in late August, as an unusually strong El Niño adds extra heat to a planet already facing background warming because of human activity. “The record is another clear signal of an ocean under growing stress,” Samantha Burgess, deputy director of C3S, told The Guardian.