Our endless summer
Warmest ever start to year
Tand he balmy first three months of 2018 have given New Zealand its hottest recorded start to a year, with mean temperatures soaring to 1.75C above average over the period.
The scorching start came amid our hottest summer on record and also included the sixth-warmest March.
April has continued in the same vein, with temperatures hitting 27C in Napier and Hastings and 26C in Gisborne and Christchurch.
WeatherWatch NZ analyst Philip Duncan said some weather stations in Hawke’s Bay and Gisborne yesterday afternoon got as high as 32C.
The belt of high pressure over New Zealand is keeping tropical lows away, and producing warm westerlies, which are behind the hot temperatures on the East Coast.
MetService meteorologist Philippa Murdoch said the ridge of high pressure would hang around the North Island for the next few days.
The North Island experienced a fine, warm autumn day. Auckland hit 23C, and Tauranga was 25C, she said. Karl Loots of MetService said although it was warm for April, it was not unseasonable weather.
“This time of year we generally get stronger westerly flows, so every now and again can see temperatures in the high 20s.”
Niwa’s just-released climate summary for last month reported the three-month period was 1.75C above the 1981 to 2010 average.
That beat even early 1998, when one of our history’s biggest El Nino events was still meddling with the weather and temperatures came in at 1.51C above average.
Last month was characterised by significantly higher pressure than normal to the east of New Zealand, which combined with a fading La Nina system to push more northeasterly winds than usual over the country.
These warm, humid air masses, combined with the remnants of the marine heatwave in the Tasman Sea, influenced higher-than-usual temperatures over the country, as well as some heavy rainfall events.
Temperatures were either “well above average” or “above average” — that’s 1.2C or 0.51C to 1.2C above the mean, respectively — nearly everywhere. Only isolated parts of Tasman and Southland experienced nearaverage temperatures.
As was observed in February, the number of record and near-record night-time temperatures was even greater than the number of record and near-record daytime temperatures. That was due to the combination of a lingering marine heatwave and warm and humid northeasterlies, which kept overnight temperatures on the high side and left many of us sleep-starved.
March rainfall was patchy across New Zealand, with heavy rain leading to flooding in some areas.
Levels were highest — or more than 149 per cent above normal — in the central North Island, the eastern North Island south of Napier, Kapiti Coast, Nelson, south Canterbury, north and central Otago, and Fiordland.
Rainfall was meanwhile above normal in Northland, the southern half of the North Island, and Tasman, but below normal in isolated patches of Auckland, Waikato, Bay of Plenty, East Cape, Christchurch, Dunedin, and Southland.
Of the six main centres in March, Auckland and Tauranga were the warmest, Wellington was the wettest and least sunny, Christchurch was the driest, Dunedin was the coolest, and Tauranga was the sunniest. The sunniest four locations in 2018 so far are Blenheim (708 hours), Richmond (708 hours), Napier (697 hours) and Lake Tekapo (688 hours).