Tauranga was the warmest city in the country last month, experiencing its second hottest December since records began in 1913.
The average temperature in Tauranga for December was a balmy 19.4C, which is 1.4C higher than normal, Niwa National Climate Centre figures show.
Te Puke had an average temperature of 18.4C, its the fourth hottest December since 1973.
"Over the whole month it was unusually warm. That was the case for a lot of people in the country," climate scientist Andrew Tait said.
Of the six main centres, Auckland was a close second with an average temperature of 19.3C and Dunedin was the coldest at 15.1C, although this was still "well above" normal.
"It's always a battle between Auckland and Tauranga who will get the warmest month. It was very close this time as well," Mr Tait said.
And if you found yourself kicking off the bedcovers a couple of days after Christmas it's hardly surprising. On December 27 the extreme minimum temperature, which is taken at around 6am, was 20.1C, the second warmest low ever recorded in Tauranga during December.
"It was significantly a very warm, even uncomfortable, night for people," Mr Tait said.
The above average temperatures, experienced throughout New Zealand, particularly the North Island, were caused by more frequent northerly and northwest winds than usual.
Nationwide the average temperature for December was 16.7C.
However, sunshine hours for the month were below normal, with Tauranga the third sunniest of the six main centres, behind Christchurch and Wellington.
Tauranga rainfall was "near normal" for December, a welcome start to the summer in comparison to the previous December, which was the fourth wettest on record.
At the end of December 2012 soils were much drier than usual in the Bay of Plenty, Mr Tait said.
But, despite the unseasonably warm weather, there has not been a drain on water resources.
Tauranga City Council does not have any water restrictions in place at the moment and consumption is still well within its capacity to supply, communication adviser Meagan Holmes said.
"This is monitored and assessed on a regular basis during summer," she said.
"Since the introduction of universal water metering in Tauranga in 2002 and the dramatic change in water use behaviour, no summer water restrictions have been needed to meet the water requirements of the community since then," she added.
The rural fire risk for the Western Bay of Plenty is "very high to extreme", which is "about standard" for this time of year, said Barry Low, principal rural fire officer for Western Bay Moana Rural Fire Authority.
"If you do start a fire it will move very fast and spread very quickly," he cautioned.
Permits were required for all outside fires in rural areas until the end of April. He reminded people that those who lit fires in rural areas that got out of control could be liable for the costs of extinguishing them.