Most of the country is in for a fine and warm start to the New Year with temperatures in parts expected to climb well above average for this time of the Kiwi summer.

Holidaymakers around the country, and particularly the upper North Island, can expect "a really nice day" as they celebrate the final hours of 2019, MetService meteorologist Andy Best said.

There might be some early morning showers tomorrow near the Hawke's Bay ranges and inland North Island, near Manawatu, before light winds will help clear the cloud and leave a fine day.

Almost all centres recorded temperatures in the mid to low teens this morning. A weak southwest flow, and the country almost entirely covered in cloud being the reason behind this uniformity. Check out the temperature at your place at https://t.co/Yjbq0jxdqz ^AB pic.twitter.com/bCFLAurgXh

— MetService (@MetService) December 29, 2019

Sunny skies will also see temperatures for Auckland (25C) and Bay of Islands (27C) reach about three degrees above average for this time of year.

Other popular New Year's Eve spots like Taupo (25C) will be a couple of degrees above average, while Tauranga (24C) and Napier (23C) will be about par for late December.

But temperatures begin to rise significantly on New Year's Day with the upper North Island expected to reach 28C, Best said.

Wairarapa and southern Hawke's Bay should also crack the 30C mark, he added.

The hot spot for the South Island was Blenheim, with 34C expected on Wednesday - about 10 degrees above average.

New Year's Eve conditions in Wanaka will be hot and dry, Best said, with a high of 31C.

The deep south and Invercargill, meanwhile, gets a rare hot spell with 29C expected on Wednesday to bring in 2020, which is about 11 degrees above normal.

Christchurch on New Year's day will reach 33C, Best added.

Much of the dry, hot weather, he said, could be attributed to a large ridge of high pressure off the country's west coast and a warm front approaching the South Island.