Warmest June ever recorded in NZ

File photo / Richard Robinson

It's now official - last month was the warmest June ever recorded in New Zealand.

The National Institute of Water and Atmospheric Research this afternoon confirmed an "exceptionally warm start to winter", with dozens of climate stations also placing in the top four for the warmest June ever recorded.

Record high mean temperatures for the month were recorded at Kerikeri, Tauranga, Te Puke, Dunedin, Stratford, Wanganui, Westport, Hokitika, Haast, Ranfurly, Secretary Island and Whenuapai at Auckland.

The nationwide average temperature in June 2014 was 10.3C, surpassing the previous record for warmest June in 2003.

There had now been nine Junes since 1909 where the departure from average has been greater than 1.0C, and of those, five had occurred since the year 2000 and eight since the year 1970.

June last year was 0.4C above normal, but it came at the start of what was the warmest winter ever recorded in New Zealand.

Calculations by independent climate scientist Dr Jim Salinger had also shown last month's mean temperature came in at 10.3C.

When factoring in 24 stations across the country, the results were 9.8C making it warmest equal with 2003.

The warm month had been put down to a lack of southerly winds, with the equatorial Pacific Ocean remaining in a neutral ENSO-state -- meaning it was influenced by neither El Nino nor La Nina patterns.

"When you have a neutral weather pattern, everything gets thrown at you, but generally speaking, we are in a warmer trend," said analyst Philip Duncan of Weatherwatch.

"We are not really seeing a prolonged period of southerlies -- we are having prolonged periods of subtropical and Tasman sea air flows -- and that's the sole reason why it's so warm."

Dr Salinger said New Zealand was tracking at 0.4C above average for the first half of the year, and the warm trend showed no signs of changing over the coming months.

In in its outlook for the next three months, Niwa predicts above-average temperatures for all of the North Island, and average or above-average temperatures for the south.

Rainfall is predicted to be either normal or below normal for the west of the North Island and north of the South Island, and near normal for the rest of the country.

Soil moisture levels were expected to be either normal or above normal in the north and east of the North Island and east of the South Island, and equally likely to be normal in the west of the North Island and the north of the South Island.