Warmest December for 71 years

New Zealand has had its warmest December in 71 years.

Last year was Australia's hottest on record and, while annual figures for New Zealand are not yet available, the National Climate Centre says the national average temperature in December was 17.5C, or 1.9C above average.

That made it the warmest December in 71 years.

Dr Jim Salinger, principal scientist for the National Institute of Water and Atmospheric Research, said the annual figures would be released next week.

The Australian Bureau of Meteorology climate summary said last year was likely to be one of the hottest on record globally.

Preliminary figures showed the global temperature was about 0.48C above average in 2005.

Dr Salinger said New Zealand was definitely getting warmer, particularly in winter when it was now on average 1C warmer than in 1900.

That was due to global warming and was most evident in the glacial retreat.

"Sub-tropical plants are also surviving much longer in Auckland."

Niwa's monthly climate summary shows the highest temperature of 31.7C was recorded at Darfield, in inland Canterbury, on December 30. A day later the mercury hit 31.5C in Napier.

But despite the high temperatures, sunshine hours were normal or below normal throughout most of the country and many parts experienced heavy rain.

Northland, eastern Bay of Plenty and Wanganui were extremely wet, with the latter experiencing its wettest December in 115 years.

Other parts were dry, however, with soil moisture deficits recorded from Hawkes Bay to Otago in the east of the country and were severe in Marlborough and Central Otago.

Deficits were also recorded in Kapiti, Wellington and Nelson.

Severe weather hit some areas, with Southland experiencing two damaging hailstorms, Rotorua tornado-like winds and Taranaki lightning strikes that left many households temporarily without power.

Of the four main centres, Christchurch was the driest and Dunedin the wettest. Rainfall in Auckland and Wellington was about normal. All four cities had above-average temperatures, but Christchurch and Dunedin had below-average sunshine hours.

In other parts, sunshine hours were less than 80 per cent of their normal level in Waikato, King Country, Nelson and coastal North Canterbury.

In Australia, the annual climate summary showed 2005 was more than 1C warmer than the average temperature between 1961 and 1990, the world standard used to track temperature change.

Federal Environment Minister Ian Campbell said he recognised that climate change was the biggest modern-day environmental challenge and it was a problem the world needed to work together on.

Australia and the United States were the only developed nations to refuse to sign the Kyoto Protocol, which calls on countries to cut greenhouse emissions by 5.2 per cent below 1990 levels by 2012.