Sunshine for the big day

Long-range forecasting suggests average temperatures in the range of 21-25C in the North Island, and 20-25C in the South Island. Photo / Greg Bowker

It will be cooler in the lead-up to Christmas but, fingers crossed, most of us should wake to a bright morning.

Holidaymakers should plan for a sunny festive season - but chilly weather in the lead-up to December 25 will mean a Christmas Day dip will be only for the brave.

It's just under five weeks until Christmas, and MetService and weatherwatch.co.nz say the signs are looking positive for golden sunshine to bathe eastern and northern New Zealand.

But those hoping to slip on board shorts and swimsuits to plunge into the sea on Christmas Day might want to think twice. MetService meteorologist Georgina Griffiths predicts chilly temperatures in coastal waters.

"We will have cool seas until Christmas and it probably will continue into next year," she said. "So taking that holiday dip may be an extra shock to the system."

The water temperatures will be the result of a turbulent El Nino spring season, which has brought cooler temperatures to much of the country.

As the festive season nears, the system will be replaced by highs parked over the North Island.

Long-range forecasting suggests average temperatures in the range of 21-25C in the North Island, and 20-25C in the South Island.

The South Island's West Coast is likely to experience the least festive conditions over Christmas and New Year. Rain is expected and westerly winds are forecast in many parts of the South Island.

"I would probably choose the North Island this year because we expect more highs to favour the North Island," Griffiths said.

"That will continue through the holiday period."

Weatherwatch.co.nz forecaster Philip Duncan said January to March would be hot and dry, meaning popular holiday spots in the east or inland New Zealand would typically be sunnier, drier and warmer.

"It bodes well for places like Coromandel, the Bay of Islands, Gisborne, Nelson, Queenstown and Taupo," he said.

A hallmark of an El Nino summer was hot and dry conditions in the east and cloudy and cool in the west.

Duncan said Auckland would probably be cloudier and cooler this summer.

But he warned the odd cold snap was still likely during summer because of southerly winds from El Nino weather patterns in the Tasman Sea.