The Paekakariki surfboat crew in action during the Piha Big Wave Classic on Auckland's west coast on Saturday. Photo / Brett Phibbs
Thousands hit the water to swim, paddle or just cool off in balmy conditions expected to last until mid-week.
The sunny weather that warmed much of the upper North Island during the weekend is likely to continue for most of this week.
A high hanging over the country has brought dry, warm conditions, and similar weather is expected until at least Wednesday.
Philip Duncan of weatherwatch.co.nz said the current recent weather pattern was "stunning" and was a sign that summer had really arrived for the northern part of the country.
In Auckland hundreds of swimmers turned out in 25.8C heat yesterday to take part in in this season's Auckland Master community swims at the Tamaki Drive waterfront.
The 3.6km events drew more than 300 entrants who had to swim from St Heliers beach boat ramp to the Tamaki Yacht Club.
On Saturday the mercury hit 23C in the city as thousands went to the west coast for the Piha Big Wave Classic - a surfboat event which is part of the Surf Lifesaving sports programme.
About 500 athletes and support crew participated in Saturday's event, which had to be delayed because of large waves caused by yesterday's king tides.
Thousands also took the opportunity to party at the Sun & Sound concert at Takapuna Beach Reserve.
The event was organised by radio station George FM.
It featured DJs and music acts, with Takapuna beach acting as a backdrop.
Mr Duncan said the high would stay over most of the North Island for the next few days but the weather could turn on Wednesday.
The upper North Island would probably be "pretty dry" for the rest of the month.
"There is a chance of some rain - there's a sub-tropical low that's going to be pushing down our way maybe around Waitangi Day but I think the high's going to be in control."
This week's weather
Today: Fine spells, light winds. 25C Tomorrow: Fine, light winds. 24C Wednesday: Fine, light winds. 25C Thursday: Possible drizzle from a low approaching from the Tasman Sea. 23C Friday: Possible drizzle. 23C