Weather on Christmas Eve is dominated by two high pressure systems, one in the Tasman Sea and one east of NZ in the Pacific Ocean.

In between these highs runs a weak trough of low pressure over the country.
For the South Island this won’t mean much, as the weather is looking pretty good in the south – with some cloud possible both morning and night, while staying mainly sunny during the day, along with onshore winds blowing in the afternoon.

For the North Island, early morning showers from Northland through to Taranaki should clear, leaving a mostly sunny late morning.
Showers will develop again in the afternoon though, right from Northland down through to parts of the lower North Island in the afternoon.
There’s a chance that one or two of these showers may be heavy – especially in the west of the North Island.
The Bay of Plenty and perhaps the East Coast may just see cloud build but remain fairly dry, while Wellington looks to stay mainly dry all day too.

– Aaron Wilkinson, WeatherWatch.co.nz