"These ones give us a bit of an idea, but as we get closer a manual forecast written by a forecaster will be more accurate."
The 10-day forecast "certainly shouldn't be taken as gospel at this stage".
Under the current forecast, Christchurch is the hottest, with a scorching high of 29 degrees.
On the other side of the South Island Greymouth is lumped with the coldest Christmas, with rain and a high of 21 predicted.
Not everyone will be unhappy about the predicted rain, with farmers in need of some wetter weather.
Wellington is currently facing a water shortage, but is among those expecting a dry Christmas.
Long range forecast for Christmas Day around the country
Whangarei: Partly cloudy, not much wind. High of 26.
Auckland: Partly cloudy, light winds. High of 26.
Tauranga: Cloudy, not much wind. High of 25.
Hamilton: Cloudy, little wind. High of 26.
New Plymouth: Rain, northerlies. High of 23.
Taupo: Rain with little wind. High of 25.
Napier: Cloudy, light winds. High of 27.
Palmerston North: Rain, northwesterlies. High of 26.
Wellington: Partly cloudy, northwesterlies. High of 23.
Nelson: Rain, northwesterlies. High of 25.
Blenheim: Partly cloudy, northwesterlies. High of 28.
Greymouth: Rain with not much wind. High of 21.
Christchurch: Partly cloudy with northerlies. High of 29.
Dunedin: Partly cloudy with northeasterlies. High of 24.
Queenstown: Showers with light winds. High of 23.
Invercargill: Rain with northwesterlies. High of 24.