It's another mostly fine day for New Zealand, and with much of the North Island hovering around or above 20C, Kiwis will be pouring to the beach to cool off.
But NIWA says Kiwis hitting the water around the country should take a look at our sea surface temperatures (SSTs).
"Coastal SSTs are running from 1C, to as much as 3C above average for the time of year," it says.
"The most unusually warm SSTs, when compared to average, are near-shore waters around the Auckland region."
The upper North Island's coastal SSTs are averaging around 18C, falling a degree or two further down towards Wellington. The South Island sees 15C/16C on its west side, and 14C/13C on its east.
But Aucklanders considering nipping for a dip face more than just warm sea temperatures. They're being warned to watch out for hot sand along the west coast, with hazard alerts in place for Piha Beach, Piha North Beach and Karekare Beach.
"Exercise caution. Beachgoers reporting sand is very hot. Foot-wear recommended," the Safeswim website reports.