Winter 2013

Warmest winter on record for New Zealand.

Temperature 

A very warm winter for most of the country, with record-high mean temperatures for winter occurring throughout the South Island.  Mean temperatures well above average (more than 1.2°C above the winter average) throughout Southland, Otago (except South Otago), inland Canterbury, coastal Canterbury north of Ashburton, and isolated parts of the lower half of the North Island.  The nation-wide mean temperature was 1.2°C above the winter average, based on NIWA’s seven-station temperature series, making this the warmest winter on record since 1909.

Rainfall

A wet winter overall for parts of Central Otago, the east coast of the South Island from Dunedin to Christchurch, and southeastern parts of Marlborough and Hawke’s Bay.  Rainfall was well above normal (more than 150 percent of normal winter rainfall) for areas of eastern and Central Otago.  In contrast, below normal rainfall (less than 80 percent of normal winter rainfall) occurred in parts of Manawatu, Taranaki, Bay of Plenty and Waikato.

Soil Moisture

As at 1 September 2013, most soils throughout New Zealand were at normal soil moisture levels for the time of year.  In isolated parts of Central Otago, coastal North Otago and about Kaikoura, soils were wetter than normal for the time of year.

Sunshine

Winter sunshine hours were above normal (110-125 percent of winter normal) for parts of western Southland, Queenstown Lakes, southern Westland, southeastern Hawke’s Bay and Gisborne. Sunshine was below normal (75-90 percent of winter normal) in parts of eastern Otago including Dunedin and Oamaru, Nelson, Marlborough, and along the southwestern coast of the North Island from Wellington to Taranaki.

Overview

Early winter 2013 was characterised by lower pressures than normal across New Zealand and to the north and northeast of the country, with persistent high pressure centres south and southeast of Tasmania.  This resulted in an anomalous east-southeasterly flow over the South Island, which contributed to well above normal rainfall totals recorded throughout areas to the east of the Southern Alps.  Of particular note was the storm of 19-21 June, which brought the strongest sustained 10-minute winds that Wellington airport has seen since 1985.  In addition, cold south-southeasterly winds associated with the storm resulted in a significant snowfall event across the South Island.  Mid-late winter was characterised by much higher than normal pressures to the east and south-east of the country, and lower than normal pressures to the north, west and south of New Zealand. This resulted in more northerly and north-easterly airflow than usual across the country.  This pressure pattern caused largely settled conditions over New Zealand for much of July and August, resulting in high mean temperatures for the time of year in many locations, but particularly throughout the South Island.

It was a very warm winter for most of the country, with mean temperatures well above average (more than 1.2°C above the winter average) throughout Southland, Otago (except South Otago), inland Canterbury, coastal Canterbury north of Ashburton, and isolated parts of the lower half of the North Island.  Numerous locations across New Zealand (but especially across the South Island) recorded their highest mean temperature for winter on record.  Near average mean temperatures (within 0.5°C of winter average) were recorded in areas of northern Taranaki, western Waikato, Coromandel, Auckland and Northland.  Elsewhere, temperatures were above average (0.5-1.2°C above the winter average).  The nation-wide average temperature in winter 2013 was 9.5°C (1.2°C above the 1971-2000 winter average, using NIWA’s seven-station temperature series which begins in 1909).  Based on this temperature series, winter 2013 was the warmest winter on record for New Zealand to date.

Overall, it was a wet winter for parts of Central Otago, the east coast of the South Island from Dunedin to Christchurch, and southeastern parts of Marlborough and Hawke’s Bay.  Rainfall was above normal (more than 120 percent of normal winter rainfall) at most of these areas.  The exception was areas of eastern and Central Otago, where rainfall was well above normal (more than 150 percent of normal winter rainfall).  This was largely as a result of the record rainfall totals that were recorded in June at these locations.  In contrast, below normal rainfall (less than 80 percent of normal winter rainfall) occurred in parts of Manawatu, Taranaki, Bay of Plenty and Waikato.  Near normal rainfall was recorded elsewhere (between 80 and 120 percent of normal winter rainfall). 

As at 1 September 2013, most soils throughout New Zealand were at normal soil moisture levels for the time of year.  In isolated parts of Central Otago, coastal North Otago and about Kaikoura, soils were wetter than normal for the time of year.

Sunshine hours for winter were well above normal (more than 125 percent of winter normal) about northern Fiordland, and above normal (110-125 percent of winter normal) for parts of western Southland, Queenstown Lakes, southern Westland, southeastern Hawke’s Bay and Gisborne. Sunshine was below normal (75-90 percent of winter normal) in parts of eastern Otago including Dunedin and Oamaru, Nelson, Marlborough, and along the southwestern coast of the North Island from Wellington to Taranaki. Near normal sunshine hours were experienced in remaining areas of the country (sunshine hours within 10 percent of winter normal).  

Further highlights:

  • The highest temperature was 22.1 °C, recorded at Winchmore on 2 June, and at Kaitaia on 13 August.
  • The lowest temperature was -12.1°C, observed at Lake Tekapo on 28 June.
  • The highest 1-day rainfall was 187 mm, recorded at Pigeon Creek, Tasman on 3 June. 
  • The highest wind gust was 202 km/hr, at Mt Kaukau, Wellington, on 20 June.
  • Of the six main centres in winter 2013, Wellington was the wettest, Dunedin was the driest, Auckland was the warmest, Christchurch was the coolest, Tauranga was the sunniest and Hamilton was the cloudiest.

Full report

Winter 2013 climate summary (PDF 926 KB)

For further information, please contact:

Dr Brett Mullan

Principal Scientist, Climate Variability and Change, NIWA Wellington

Tel. 04 386 0508