The latest Christmas Day weather forecasts show thunderstorms, downpours and cooler-than-average temperatures could cause a more than a few miserable BBQs.
NIWA's models show locally-heavy rain falling on the big day over parts of the North Island.
"Our test ensemble modelling (model run 18 times at once) continues to show a 'signal' for heavy rain mid-week," NIWA says on Twitter.
"If you've plans to travel or enjoy the outdoors Christmas and Boxing Days over parts of the North Island, keep up-to-date on the forecast."
MetService's Christmas Day weather forecast shows a "mixed bag" of weather arriving on the 25th.
"Those celebrating in Taupo, Waikato, Waitomo and Taumaranui that plan on heading out in the afternoon to work off that Christmas lunch should be aware heavy showers are forecast with thunderstorms and downpours possible in localised areas," it says on Facebook.
"Cloud and cooler-than-average temperatures are forecast over the east of the South Island could also mean donning those togs and heading into the water may be a less attractive prospect for those who are faint of heart."
On the positive side, Auckland is forecast to have sunny spells with only the chance of a shower, keeping the city on track to hit 23C - the warmest of the main centres.
"Boxing Day weather is looking to be similar to Christmas with showers continuing over the central North Island through the east of the South Island looks to finally break free of the cloud as the day progresses, even if isolated showers are likely to persist," MetService says.
