Dreaming of a sunny Christmas? What weather forecasters are saying

Start getting out those picnic blankets and BBQs - the weather for Christmas Day is looking relatively decent.

Forecasters are cautiously pointing to a settled December 25 thanks to a high pressure area that's expected to hover out in the Tasman Sea.

It probably won't be baking hot, and some areas might even get some rain but nowhere is expected to be a washout at this stage, according to MetService.

That will come as welcome news for waterlogged regions like Canterbury and Manawatū where torrential rain has caused widespread flooding this week.

MetService meteorologist Lewis Ferris said an area of high pressure was "very likely" to be close to the country, which was good news as it meant relatively settled weather - although being 10 days away, things could change.

Ferris was not promising high temperatures and a perfectly sunny Christmas Day everywhere.

"There is a possibility that some rain will move across the country but it doesn't look like there'll be a washout of anyone at this point."

The exact position of the high couldn't be predicted yet, but it was likely to sit west of the country, which meant potential southwesterly winds moving on to the South Island - bringing slightly cooler than average weather further south.

The Deep South might get temperatures in the mid-teens, the middle of the country could hover around the high teens or 20C, while the northern and central North Island could see the mid-20s.

Most of the North Island would be in for a drier day, but there could be some rain, most probably in the southwestern parts of the South Island. There was a chance that rain could also sneak up the east coast to Canterbury.

The torrential rain of the past couple of days has seen near-record rainfall in places like Christchurch and Ashburton, while at least 114 homes were flooded in Feilding overnight.

Ferris said that big weather system was on its way out, with a good area of high pressure for this Saturday and Sunday.

Rain cloud continues to affect central parts of NZ, and also eastern areas from Canterbury to Southland. Meanwhile, the sun continues to shine on much of the West Coast, and shower cloud covers northern NZ https://t.co/rcECVuGXOw ^PL pic.twitter.com/2xubXiWDTR

— MetService (@MetService) December 15, 2021

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Niwa is also forecasting a decent Christmas Day, with the really hot weather coming in the last week of the year.

Speaking to TVNZ's Breakfast this morning, Niwa principal scientist Chris Brandolino said the current heavy rain in many parts of the country was due to La Niña, with northeasterly winds and warm air flow dragging moisture in and causing heavy rain.

He said a hallmark of summer would be "binge rainfall" - long dry periods followed by heavy downpours. That would bring an increased threat of flooding and slips.

🔴 High pressure for the holidays❓— still a little early for specifics!

As tropical moisture finally moves away, high pressure is forecast to move overhead from this weekend into early next week 👍

Looking toward Xmas, another area of high pressure may approach from the west. pic.twitter.com/ahHZ612Usx

— NIWA Weather (@NiwaWeather) December 15, 2021

Thankfully the next dry spell is imminent. Brandolino said in the South Island today and Friday could be chilly, warming up by Sunday and Monday, especially in the east.

From Sunday the North Island would also see warm temperatures, with potential for strong winds on Thursday and Christmas Eve.

December 24 and 25 could be a little chilly in the south, while they should be warm in the upper half of the North Island, he said.