Northland's Christmas Day weather forecast - it's not great

Santa will need his brolly in Northland next week with rain, possibly heavy, forecast for Christmas Eve and Christmas Day across the region.

Brollies and rain macs, rather than sunscreen and parasols will be the order of the day in Northland on Christmas Day with rain, possibly heavy, forecast for the region.

Northlanders often say that it rains on Christmas Day in the region and recent history shows they are right, with more forecast for the big day on Tuesday.

MetService meteorologist James Millward said the weather was looking pretty foul for Northland from today, when a low pressure system from the northwest is expected to start dumping rain across the region.

''It's not looking very good up there for Christmas. [Today] will have rain developing in the afternoon and it will last until early next week when another low pressure system will follow, bringing more rain,'' he said.

''At this stage it's looking like Christmas Day itself across Northland will have rain, and it may be heavy, before things start to clear up on Boxing Day.''

There was a chance that things could start to clear up on Christmas Day afternoon, but it was too far out to confirm at this stage and Millward urged people to keep up-to-date with the latest forecasts at www.metservice.com.

''But I suppose the good news, if there is any, is that at least it won't be cold, with daily highs of 23-25C and overnight lows of 15-17C.''

The forecast rain may not be a big surprise to Northlanders though.

Niwa figures show that when it comes to Northland, Whangārei has had 10 wet Christmas Days in the past three decades, meaning a wet Christmas occurs, on average, once every three years. The wettest Christmas on record was in 1993 when 31.6mm of rain hit the city.

Kaitaia has had nine wet Christmas Days in the past 30 years, meaning a wet Christmas occurs, on average, once every 3.3 years. The wettest Christmas on record there was in 1979 when 45.8mm of rain fell.

The last year Whangārei and Kaitaia had a wet Christmas Day was in 2013, with the longest stretch where both centres did not have rain on Christmas Day being four years from 2008-2011.

A day is deemed wet if more than 1mm of rain falls between 9am that day and 9am the next.