The balmy first three months of 2018 has 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 ever observed in the country.

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.

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A flooded vineyard in Hawke's Bay's Esk Valley on March 8. Photo / File
A flooded vineyard in Hawke's Bay's Esk Valley on March 8. Photo / File

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 heat wave 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 near-average 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 day time 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 spatially patchy across New Zealand, with heavy rain leading to flooding in some areas.

Source / Niwa
Source / Niwa

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.

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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.

From the books

• The highest temperature was 31.8C, observed at Kawerau on March 5.
• The lowest temperature was -1.8C, observed at Middlemarch, Otago, on March 17.
• The highest one-day rainfall was 205 mm, recorded at Fiordland's Secretary Island on March 19.
• The highest wind gust was 176 km/h, observed at the West Coast's aptly-named Cape Foulwind on March 13.
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.
• Of the available automatic sunshine observation sites, the sunniest four locations in 2018 so far are Blenheim (708 hours), Richmond (708 hours), Napier (697 hours) and Lake Tekapo (688 hours).