New Zealand had its hottest ever recorded year in 2016, Niwa climate summary says
New Zealand experienced its warmest year on record in 2016.
Annual temperatures were above average throughout the country, making the year 2016 the warmest since records began in 1909, Niwa's annual climate summary, released on Monday, said.
Last year's nation-wide average temperature was 13.4 degrees Celsius; 0.8 degrees above the 1981–2010 annual average.
Niwa pulls its temperature data from between 400 and 450 stations scattered around the country. Out of these, 75 observed record or near-record highs in 2016.
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Thirty-three hit their highest ever temperatures, on record, with Masterton making a whole two degrees Celsius leap up from its average.
Niwa forecaster Chris Brandolino said last year's "exceptional warmth" was the result of three factors.
Firstly, "as an island nation we are very susceptible to ocean temperatures - and these were higher than usual", he said.
Secondly, sea pressures were higher to the country's east, and lower in the south and west. That combination caused more northerly and northwesterly winds to blow across our landmass than usual, Brandolino explained.
Northerlies are the warmer winds, as southerlies bring cooler air from the Antarctic along with them.
Thirdly, climate change.
"New Zealand warmed by almost a degree over the last 100 years due to greenhouse gasses," Brandolino said.
He said warming due to greenhouse gasses looked to be a constant for the foreseeable future, while ocean pressure and temperature were variables difficult to forecast more than three months in advance.
Temperatures soared especially high in Northland, Auckland, Bay of Plenty, Hawke's Bay, Whanganui, Manawatu, Kapiti Coast, Wellington, West Coast, Otago and Southland.
Near-average temperatures - within 0.5 degrees Celsius of the annual average - were only observed at a smattering of South Island locations, including parts of Tasman, South Otago, Timaru and Oamaru.
Not a single location experienced below-average temperatures, and only August and December had nationwide lower-than-average temperatures.
The first seven months of the year from January to July were remarkably warm, with the nationwide average temperature higher than average for each month respectively.
The three warmest months in 2016 were February (2.2 degrees above average), May (2.1 degrees above average) and June (1.6 degrees above average).
As a whole, annual rainfall totals for 2016 were near normal for much of the country, Brandolino said.
However, they were above normal for parts of Kapiti Coast, Tasman, West Coast and Fiordland. Milford Sound was especially sodden and observed its wettest year on record (9259mm, 138 per cent of the annual normal).
Wellington's Hutt Valley experienced a month's worth of rain in 24 hours during November, but Brandolino said that "particularly heavy rain event" did not translate to a wet year in general.
Rainfall was below normal in parts of the eastern North Island south of Napier, and parts of the eastern South Island north of Christchurch.
The below average annual rainfall for some eastern parts of New Zealand was reflected in soil moisture levels during the year.
In June 2016, a drought classification for the east coast of the South Island was extended until the end of December 2016; the drought had been officially declared on February 12, 2015.
Soil moisture levels from the Waikato up to Northland dropped dramatically in December.
Brandolino said soils in the Far North especially were "very to extremely abnormally dry for this time of year".
In terms of sunshine, Richmond, near Nelson, got the most with 2840 hours of sun in 2016.
It was followed by Blenheim with 2582, Takaka with 2534, and New Plymouth with 2503.
Across the ditch, Australia recorded 2016 as its fourth warmest year on record.
Last year was the US and Singapore's second warmest on record.