Duncan urged people to get out of the main centres if they wanted to lap up the sunshine as the holiday hotspots would enjoy some of the best weather.
"Coromandel, Hawke's Bay, Taupo, east Bay of Plenty, East Cape and Marlborough - those areas are looking pretty good.
"It's Mother Nature's way of saying, 'Get out of the city and go on holiday.'"
Duncan said the calmest, driest weather would be in the north and east. But holidaymakers should still pack a woolly jumper as temperatures would drop. The South Island could expect to be around 11C to 17C while the North Island would be a bit warmer in the low 20Cs.
Duncan warned the weather was set to go downhill again on Sunday as New Zealand is stuck in a late spring pattern which is bringing changeable weather to the country.
"We have to get used to the cloud, it's going to be with us until the second week of January.
"Every year we get asked 'Why isn't the weather perfect?' But we're two islands in the Roaring 40s.
"It's called Aotearoa for a reason with the amount of cloud we get."
Duncan said Southland would get the coldest weather, while Hawke's Bay and East Cape would get the hottest. The wettest place would be the west coast of the South Island and the cloudiest the northwest.
Duncan said Kiwis shouldn't lose hope for a good, strong summer. He thought there could be a "dramatic change" in late January or early February. A heatwave from Australia or a wet tropical event from the Pacific could find its way to New Zealand.
