Most of the North Island will be experiencing average weather conditions for this time of year.
Wellington will be a little cooler than usual with a high of 18C but the wind and rain should stay away.
"It's actually meant to be a heck of a lot better than last year for Wellington," Harris said.
Though mostly fine in the South Island, temperatures are expected to be lower than normal for this time of year - especially in Christchurch and Dunedin.
Santa may need to pack a jumper as he heads through Gore - it's forecast to be the coldest spot in the country with a high of 14C.
The good news for Southland and Otago is temperatures in general are starting to creep up a degree or two, bringing warmer weather in the afternoon and evenings when the sun decides to stay out, WeatherWatch says.
Ferris said as it is still four sleeps until the big day forecasts could change and he advised people to check weather reports daily for updates.
Niwa meteorologists say conditions are looking pretty good compared with last Christmas.
"Last Christmas Eve, more than 100 people were evacuated overnight after flooding at Waihī Beach. On Christmas Day there were several localised thunderstorms, floods and slips in Napier, Whanganui and the Coromandel Peninsula," a Niwa spokesperson said.
"It was a different much more pleasant occasion in the South Island where Cromwell hit 32.8C on Christmas Day, the warmest temperature recorded across all of New Zealand in December 2018."