Climate summary for May 2017

Cool and dry for much of the South Island, wet for inland parts of the North Island

Temperature

May temperatures were below average (-0.51 to -1.20°C) for eastern and inland parts of the South Island, southern Hawke’s Bay and Wairarapa. Pockets of well below average temperatures (< -1.20 °C) were observed in Tasman, south Canterbury, Mt Cook and southern Central Otago. May temperatures were typically near average (-0.50°C to +0.50°C) for the remainder of the country.

Rainfall

 

Rainfall was well below normal (< 50%) for many eastern and inland parts of Canterbury, as well as Milford Sound.  Below normal rainfall (50-79%) was recorded in Otago, southwestern parts of Southland and the Far North.  In contrast, rainfall was well above normal (>149%) for the central North Island and Tasman, and above normal (120-149%) for parts of Nelson, Marlborough, Manawatu, Gisborne and Bay of Plenty.

Sunshine

Sunshine was well above normal (> 125%) in southeastern parts of Otago, the Southern Lakes, and Taumarunui.  Above normal sunshine (110-125%) was recorded in parts of Northland, Auckland, southern Hawke’s Bay, coastal Wairarapa, Marlborough and the Mackenzie Country. Sunshine was typically near normal (90-109%) for the remainder of the country.

Soil Moisture

As at 1 June 2017, soil moisture levels were below normal for the time of year for large parts of Southland and inland Otago. Soil moisture levels were above normal for eastern parts of New Zealand, especially in Marlborough.

Climate summary and extremes for April 2017

Overview

Overall, mean sea level air pressures were higher than normal over and to the southwest of New Zealand during May. This resulted in more easterly winds than normal over the North Island, and these winds delivered more rainfall than normal to many eastern and inland parts of the North Island. In the South Island, the air pressure anomaly for the month resulted in more southerly winds than normal. These southerlies delivered cool temperatures to many southern, eastern and inland parts. In addition, the higher than normal air pressures generally provided settled weather with clear skies, particularly in southern-most parts. As a result, much of Southland and Otago observed a relatively dry and sunny month overall.

Further highlights

  • The highest temperature was 23.4°C, observed at Waione on 10 May.

  • The lowest temperature was -6.9°C, observed at Middlemarch on 22 May.

  • The highest 1-day rainfall was 176 mm, recorded at Milford Sound on 2 May.

  • The highest wind gust was 167 km/hr, observed at Akitio on 19 May.

  • Of the six main centres in May 2017, Auckland was the warmest, Christchurch was the coldest, Dunedin was the driest, Wellington was the least sunny, and Tauranga was both the wettest and sunniest. Tauranga received most its total rainfall for May on just five days, while remaining days of the month were fairly settled and sunny.  See May Climate in the six main centres section for further explanation.

  • Of the available, regularly reporting sunshine observation sites, the sunniest four locations in 2017 so far (1 January – 31 May) were Whakatane (1145 hours), Blenheim (1104 hours), Richmond (1089 hours) and Lake Tekapo (1076 hours).

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Contact

Mr Chris Brandolino, Principal Scientist – Forecasting, NIWA National Climate Centre
Tel. 09 375 6335, Mobile 027 886 0014