Freezing start to day - but it's looking glorious for next two days

Much of the country is waking to one of the coldest mornings this spring with freezing temperatures and even frosts in parts of the North Island.

The day has a distinctly wintry feel in Masterton and Taupo, where the temperature was 0C at 6am.

It's not much warmer in Palmerston North, Queenstown and Hamilton, all sitting on a chilly 3C.

Even Auckland felt a nip on 7C. Only the top of both islands managed to enjoy a slightly warmer start as the mercury hovered around 12C.

MetService said most of the country was experiencing a cold start to the day and even the chance of frosts in places.

A cold start today for many, even frost. Hope you covered those tender plants. https://t.co/Yjbq0jxdqz ^Cam pic.twitter.com/FJqHzFVrZA

— MetService (@MetService) October 18, 2017

But the bracing start was going to give way for a stellar day across the South Island where temperatures are expected to soar thanks to a mini-heatwave.

Alexandra will soar from a wintry 3C to 26C by the afternoon as southern regions enjoy an unseasonal heat wave.

MetService said after the chilly start temperatures would climb throughout the day across much of the country.

They were expected to rise to above average for most of the South Island today and tomorrow.

Niwa said the southern spring sizzle may be so hot it could challenge temperature records in some inland regions.

MetService said the country would be bathed in summer-like conditions for the next 48 hours before a front hits over Labour Weekend.

Weather forecast.