Break out the woollies - chilly blast coming

Chilly weather is heralding winter's approach with frost and snow likely for the south of New Zealand next week.

Meteorologists stopped short of describing it as an arctic blast but said the cooler air coming from the South Pole would be widely felt when temperatures plunged 5 to 10 degrees.

Niwa meteorologist Ben Noll said a cold blast early next week would be followed by another, more aggressive one, close on its heels at the end of the week.

"Certainly colder conditions than it's been, especially in the South Island where there may be some frost and some snow in the higher elevations.

"In the North Island, no snow just yet, but you are certainly going to want to bundle up."

He said it might be time to flip the summer wardrobe of T-shirts and jandals and pull out the winter gear.

Noll said the temperatures, which could dip below zero in the Central Plateau and areas in the south prone to chillier weather, would be felt more acutely because of the recent milder temperatures.

The meteorologist said the warmer weather was one positive of the recent flurry of stormy weather.

"It's a flow-on effect from the storms. They brought a lot of rain, but they come from the north and brought with them more tropical warmer air."

Noll said winter was quickly approaching, but those who preferred the warmth would be happy to hear the milder weather would return mid-May.

"The door will open back up to the milder weather in May and it does look relatively dry."

Noll advised people to make the most of this week before the cold took hold.

Enjoy the pleasantly mild air while it's still here -- long range model guidance indicates a notably chillier pattern arriving next week 🌬 pic.twitter.com/hgoEMi0e07

— NIWA Weather (@NiwaWeather) April 25, 2017

The sun is set to give way to heavy cloud and rain by the end of the week, making for a short-lived reprieve barely a fortnight on from Cyclone Cook.

MetService meteorologist April Clarke said the weather would turn wet tomorrow or Friday, particularly at the southwestern end of the country.

"On Wednesday and Thursday, most of the country remains sunny apart from areas of morning cloud or fog," she said. "However, places west of the alps deteriorate into rain with a front approaching from the west."

Parts of the country worst hit by the torrential rain in recent weeks will not escape either; the MetService predicts heavy rain in the northeast of the country later in the week.

"There is then a moderate risk that rainfall accumulations will reach warning amounts in the north of Westland, Buller, Nelson, the north of Marlborough and over the North Island from Taranaki across to the Bay of Plenty northwards."

Given the incoming inclement weather it could be wise to make the most of what's expected to be a sunny day today.

In the main centres today, Auckland was expected to be relatively warm and sunny with a high of 21C; in the capital a few more clouds were forecast and a cooler high of just 17C was forecast.

Christchurch would start the day with low cloud and fog, but this would give way to the sun later in the day.