Holidaymakers might be enjoying one of the hottest summers on record, but swimmers are finding the water colder than usual.

Temperature readings have confirmed beach-goer reports that the water is chilly, but it is perhaps not quite as chilly as they might think.

Swimmer reports including the comments "brrrr" and "it's bloody cold" prompted the Bay of Plenty Times to seek expert confirmation.

Metservice meteorologist Lisa Murray scanned monthly data and found that water temperatures had been relatively cool around most of New Zealand's coast apart from at some regions in the South Island.

Advertisement

"Up where you guys are it's a little bit cooler, but not much cooler than usual," she said.

On average, the water at Tauranga had been 0.25C chillier than normal in December.

When asked if beach-goers would notice such a small difference, Ms Murray said that a person who swam regularly could well notice it.

"Someone who's in the water over the whole month, they will feel it," she said.

Tauranga's harbour water was measured yesterday at 18.4C, and was forecast to remain at a similar temperature for the next week.

A Niwa climate scientist earlier said that this year was the hottest-ever for Tauranga and Te Puke, with the summer also forecast to be warmer than usual.

The scientist, Brett Mullan, said air temperatures at Tauranga Airport and Te Puke were on average about 1C warmer than normal.