Born to be mild: NZ's sixth-warmest winter

The sun sets as fishermen cast their lines off the old Mangere Bridge in Auckland on August 12. The city saw near-average temperatures over winter. Photo / Dean Purcell

If you haven't dug too far into the firewood this year, there's a reason - New Zealand just had its sixth-warmest winter on record.

Figures released by Niwa today show winter temperatures were above or near average for most of the country - and well above average in north Canterbury and a few other isolated inland spots.

Mean temperatures for New Zealand were near average during June, and above average during July and August.

The nationwide average temperature for winter was 9C - 0.6C warmer than the 1981-2010 average, and the sixth-warmest in more than a century of records.

Near average mean temperatures were recorded in Auckland (11C or 0.4C above normal) Hamilton (9.3C or 0.1C above normal) and Tauranga (11.2C or 0.5C above normal).

The other three main centres, meanwhile, saw above average temperatures, with 10.2C in Wellington (0.9C above normal and its third-warmest winter on record), 7.5C in Christchurch (1C above normal) and 7.8C in Dunedin (0.6C above normal).

It was a particularly warm winter in North Canterbury, where Cheviot, Medbury and Waiau each observed their warmest winter on record.

Well above average winter temperatures - reaching 1.2C or more above the winter average - were also observed in Taupo, Arthur's Pass and Roxburgh.

The highest winter temperature was 22.3C, observed at Kaikoura on July 21, while the lowest was -10.4C, recorded at Mt Cook Airport on June 3.

The season got off to a relatively settled start for much of the South Island, with record or near-record low rainfall totals for June in several places.

In contrast, northern and eastern parts of the North Island bore the brunt of heavy rainfall events which resulted in significant flooding about East Cape.

During July, there were more northwesterly air flows than normal, which delivered mild temperatures to the country, amid abundant rainfall to the western South Island.

For eastern areas, however, July was much drier than usual.

August also saw more northwesterly airflows than normal, resulting in ongoing dryness for many parts of Canterbury and Otago.

Throughout the season, the polar jet stream was weaker than normal to the south of the country, which stopped long-lived cold periods and contributed to a lack of snowfall for some ski areas in the South Island.

Of the six main centres, Tauranga was the warmest, wettest and sunniest, Dunedin was the driest, Christchurch was the coolest, and Wellington was the least sunny.

While rainfall levels were below normal in eastern and inland parts of Canterbury and Otago, they were above normal in in isolated parts of Marlborough, Kapiti Coast, Manawatu and the Bay of Plenty.

For the coming three months, Niwa had forecast average temperatures for everywhere except for the north and east of the North Island, where near average temperatures were most likely.

Also in those areas, rainfall levels would most likely to near normal, while the rest of the country would receive either near or below normal amounts.

There was also a 65 per cent chance of a slow shift toward an El Nino climate system, which would become fully established by March if it eventuated.