KEY POINTS:
December and January are shaping up to be "a little bit cooler and a bit windier" than usual, says climate expert Jim Salinger.
"Our November-to-January outlook was for average and below average temperatures and probably we are looking at more southwesterly winds than usual," said Dr Salinger, of the National Institute of Water and Atmospheric Research.
"Last December was very warm. I think it was about the third warmest on record or something, so I suspect it will feel cooler than last time."
Unfortunately, there is no specific forecast for Christmas Day. "All we can do is paint a broad-brush-type picture."
Dr Salinger said it could be drier than normal in the east of the North Island because it was sheltered from the southwesterlies. And sunshine hours? "I wouldn't think it would be particularly unusual in terms of low or high."
Dr Salinger said New Zealand was in an El Nino climate pattern. "What it does is usually gives more westerlies and southwesterlies."
Sea temperatures were cooler than normal "and we wouldn't expect that to change greatly".
Above normal rainfall is forecast for the west of the South Island but the rest of the country can expect normal or below normal rainfall.
The risk of a tropical cyclone during the cyclone season - November to May - is normal, meaning there's an 80 per cent chance of an ex-tropical cyclone passing within 500km of New Zealand.
