Cyclone Evan's going to put a bit of a dampener on Christmas - it's likely to be wet, hot and humid.

The remnants of the tropical cyclone which hit Samoa and Fiji are set to reach New Zealand around Christmas Eve.

Weather Watch chief analyst Philip Duncan said there would be strong winds and rain around the top of the country.

"But then the rain will become more patchy and light ... so it'll be cloudy on Christmas Eve and very humid too."


But the Christmas Day humidity will be worse.

"This is where the humidity really comes in, pouring in," Mr Duncan said.

And it's likely to feel even hotter than that. "If the sun comes out with that humidity it might feel like the low 30s - it'll be very, very hot for the top of New Zealand."

MetService chief forecaster Peter Kreft said despite the likely unsettled nature of the weather on Christmas Day, it should be warm and not particularly windy in most places.

"So, Christmas dinner outside isn't completely off the table for everyone," said Mr Kreft.

He said by December 25 Evan would be over the Tasman Sea, maintaining a warm, humid northerly flow over much of the country.

"Rain over northern New Zealand should have eased but not be completely cleared. However, rain is likely to spread into Nelson and the West Coast of the South Island."

Mr Kreft said the driest places were likely to be in the east from Wairarapa to Canterbury.

And as New Zealanders head out to hit the sales on Boxing Day, Cyclone Evan is set to fizzle out.

"Evan pretty much dies on Boxing Day," Mr Duncan said.

And while it's outside the 10-day forecast, New Year's Eve could be "pretty good", Mr Duncan said.