Winter 2016

A warm winter for most and dry in eastern Canterbury.

Overview

Winter 2016 got off to a warm start, with the 3^rd-warmest June on record and the 10^th-warmest July on record. During the first two months of the season, winds were frequently from the north and west, while sea surface temperatures around New Zealand were warmer than average (especially to the north and west). These two factors worked in tandem to bring unusually mild temperatures to the country and contributed to a delayed start to the ski season.

In August, the seas surrounding New Zealand cooled (but were still slightly above normal), and southerly and south-easterly winds became more frequent. As a result, August was the first cooler than average  month of 2016.­ Snow settled to sea level in parts of the South Island during the first week of August and overloaded transmission lines in the Hawke’s Bay leaving thousands without power (see Highlights and extreme events section for more detail). The arrival of milder temperatures at the tail end of the season meant that winter temperatures as whole were generally near average (-0.50°C to +0.50°C of the winter average) or slightly above average +0.51°C to +1.20°C above the winter average) for most New Zealand locations. The nation-wide average temperature in winter 2016 was 9.0°C (0.6°C warmer than the 1981-2010 winter average, using NIWA’s seven-station temperature series which begins in 1909). This makes the winter of 2016 the 8^th-warmest winter on record.

The warmer than usual ocean surrounding New Zealand for much of the winter not only contributed to unseasonable warmth on land, but also created an environment that was more conducive for strong storms. Consequently, northern and eastern parts of the North Island saw a number of floods during the winter months as described in the Further highlights section. Periodic heavy rain meant that rainfall for the season as a whole was either above normal (120-149% of the winter normal) or well above normal (> 149% of the winter normal) for parts of the Bay of Plenty and Hawke’s Bay. Heavy rain events which caused flooding during June and August for Auckland and Northland were not enough to leave an imprint on seasonal rainfall however, where the amount of rain received for the upper North Island was near normal for the winter as a whole.

The prevalence of winds from northerly and westerly directions during the first two months of winter was reflected in the rainfall totals observed in central and eastern Canterbury and coastal Wairarapa. These areas were often in the rain shadow of the prevailing winds and very dry as a result. Well below normal rainfall (< 50% of the winter normal) was observed there and by the end of winter 2016 seasonal soil moisture levels were also below normal. Soil moisture levels for the remainder of the country were near normal for the time of year.

Winter sunshine was plentiful across the South Island as well as parts of Waikato and Hawke’s Bay. Well above normal sunshine (>125% of normal) was observed for coastal Otago, Canterbury and Wairarapa locations.

Further highlights:

• The highest temperature was 25.1°C, observed at Napier on 10 June.
• The lowest temperature was -14.1°C, observed at Mt Cook Airport on 8 August.
• The highest 1-day rainfall was 225 mm, recorded at North Egmont on 13 July.
• The highest wind gust was 195 km/hr, observed at Cape Turnagain on 24 July.
• Of the six main centres in winter 2016, Auckland was the warmest and wettest, Christchurch was the coolest, driest and sunniest and Dunedin the least sunniest.
• Of the available, regularly reporting sunshine observation sites, the sunniest four locations in 2016 so far (1 January – 31 August) were Richmond (1855 hours), Blenheim (1708 hours), New Plymouth (1646 hours) and Takaka (1632 hours).

Download

Download the full Winter 2016 Climate Summary report. [PDF 600KB]

Contact

For further information please contact:

Mr Chris Brandolino NIWA Forecaster – NIWA National Climate Centre Tel. (09) 375 6335, Mobile (027) 866 0014.