The sun brought the crowds to Auckland's Parnell Baths, where the water temperature in the main pool was 20.5C yesterday.
"It's been a lot busier, we've had lots of family groups come through," a staff member said.
The water temperature at Mangawhai Heads beach was still a very spring-like 15.8C, two degrees short of the average for early December, according to surfing website surf-forecast.com. There were few swimmers in the chilly waters on Saturday afternoon and possibly as many or more beach-walkers. It was a similar story at Long Bay yesterday morning, with no rush to venture into the briny.
Swimmers were instead massed at Bayswater, on the North Shore, for the 2.9km Ocean Swim series event crossing the Waitemata Harbour.
Much of the North Island can expect drizzle tomorrow, with rain developing on Wednesday.
MetService duty meteorologist Mariken van Laanen could offer no advice on about Christmas Day, which is well beyond the MetService's 10-day forecasts.
Weather report
Yesterday's maximum temperature and today's forecast:
•Whangarei 23C; mostly cloudy, occasional drizzle.
•Auckland 22C; mostly cloudy, occasional drizzle.
•Hamilton 21C; some morning cloud, then fine.
•Tauranga 25C; some morning cloud, and evening drizzle.
Wellington 18C; cloud, breaking up by afternoon.