Summer Series 2017 - NIWA's Year of Weather

SHARE THIS: 

Four seasons with a little bit of everything. It started with the bummer summer… then came the fires, rain, flooding and a very weird November. But it’s all in a year of weather as NIWA wraps up the seasonal highlights.

SUMMER – December 2016, January, February 2017

  • Highest temperature 35.5°C, at Wairoa on February 6
  • Lowest temperature -1.7°C, at Mt Cook Airport on January 5
  • Highest 1-day rainfall 309mm, at Milford Sound on January 31
  • Highest wind gust 178km/h, at Akitio on February 13

Of the six main centres:

Tauranga – warmest and sunniest

Dunedin – coolest

Christchurch – driest

Wellington – wettest and cloudiest

In the capital it was dubbed “the bummer summer” and for New Zealand generally, temperatures were cooler than usual. But in parts of Northland, Gisborne and Hawke’s Bay very warm afternoon temperatures were exacerbated due to ongoing dryness heating the air close to the ground.

A medium-scale adverse event was classified for Northland’s drought following several months of low rainfall.

High winds hit much of the North Island on January 21. Roofs came off and a bouncy castle got tangled in power lines in Kumeu. Thousands of homes were without power in Auckland and Taranaki. A car was blown off the road in Hawke’s Bay. The same storm dumped snow on mountains in the South Island, including 30cm at Cardrona, the largest in living memory according to staff.

On February 13 scrub fires on Christchurch’s Port Hills got out of control and were unable to be fully contained. The fires continued to burn for several days. A change in wind on February 15 pushed one fire toward local landmark, the Sign of the Kiwi and forced the evacuation of homes around Governors Bay. Another consumed the new Christchurch Adventure Park.

AUTUMN – March, April, May

  • Highest temperature 33°C, at Leeston on March 17
  • Lowest temperature -6.9°C at Middlemarch on May 22
  • Highest 1-day rainfall 231.8mm, at North Egmont on March 11
  • Highest wind gust 167km/h, at Akito on May 19

Of the six main centres:

Auckland – warmest and sunniest

Tauranga – wettest

Dunedin – driest and coolest

Wellington – least sunny

Christchurch – coolest

Autumn was a season of extremes – significant rain at the top of the country during March and April caused severe flooding and slips around Auckland, Coromandel and the Bay of Plenty as well as the top of the South Island.

In contrast, Southland, Central Otago and the West Coast saw drier than normal conditions as they were sheltered from the predominant easterly flow.

New Zealand was hit by the Tasman Tempest in the first week of March, when strong and slow moving low pressure, deep tropical moisture and a blocking ridge of high pressure combined to produce more rain in two days than would normally fall for an entire month for parts of the upper North Island.

And that was just the start. Then came ex-Tropical cyclone Debbie at the beginning of April which caused widespread flooding and damage in the North Island and prompted the evacuation of Edgecumbe due to rising water on the Rangitaiki River.

A week later ex-Tropical Cyclone Cook and prompted a state of emergency declaration in the Bay of Plenty. Cook made landfall near Whakatane. Towards the end of May temperatures were dropping, fog caused havoc and Wellington and Auckland airports and the first significant snowfall occurred in southern parts of the South Island.

The rain led to 35 locations recording their wettest or near-wettest autumn on record – this included all main centres with the exception of Dunedin. Whangaparaoa managed 791mm or a massive 294% of normal. By the end of autumn soil moisture was well above normal. Temperatures were also above average.

April saw the evacuation of Edgecumbe due to rising water on the Rangitaiki River. Floodwaters reached as high as 1.5m in the town.

WINTER – June, July, August

  • Highest temperature 23.2°C, at Kaikoura on August 17
  • Lowest temperature -14.6°C, at Tekapo on July 29
  • Highest 1-day rainfall 161mm, at Oamaru on July 21
  • Highest wind gust 170km/h, Akitio, Hawke’s Bay, on August 13

Of the six main centres:

Auckland – warmest

Dunedin – driest

Tauranga – sunniest

Christchurch – coolest

Wellington – wettest and least sunny

A winter that was wet, wet, wet – especially in eastern South Island. What was settled weather in June, with record to near-record low rainfall totals in a number of North Island locations, quickly turned to abundant and beyond rain in July.

There was record-breaking rain for parts of Canterbury and Otago, leading to severe flooding and prompting several declarations of states of emergency. August was warm across the country.

Oamaru had its wettest winter since records began in 1941 with 285mm recorded. But 161mm of that fell in 24 hours on July 22. But if Oamaru was wet, Invercargill was basking in sunshine – recording its sunniest winter in 104 years.

Lauder, Central Otago and home to NIWA’s atmospheric research station, recorded its warmest winter since records began in 1924. In fact its mean minimum temperature was 0.0°, making this winter the first time on record it has not been below freezing.

Meanwhile, on July 1 up to 30 vehicles had to be towed out of the South Island back country when they were snowed in. On July 6 more than 700 lightning strikes were recorded across Auckland and on July 13, strong winds struck Wellington, Interislander ferries were cancelled and waves of 10m were observed.

But overall, winter was sunnier than normal and temperatures above or well above average from Northland to the Southern Lakes.

SPRING – September, October, November

  • Highest temperature: 33.3°C, at Cromwell on November 23
  • Lowest temperature:  -6.4°C, at Mt Cook Airport on September 4
  • Highest 1-day rainfall 126mm, at Hanmer Forest on September 18
  • Highest wind gust 169km/h, at Akitio on November 8

Of the six main centres:

Auckland – warmest and least sunny

Dunedin – coolest and driest

Hamilton – wettest

Wellington – sunniest

Spring is known for being unsettled and it started off that way with regular bouts of rain moving across the country. But in November, save for a short sharp burst of snow in parts of the South Island early on, New Zealand got an extended period of very warm and dry weather due to a persistent ridge of high pressure.

The average nationwide temperature was 13°C – the second warmest spring on record. Rainfall was below normal in Auckland, Kapiti Coast, Wellington, Nelson, Marlborough, inland Canterbury, Otago and Southland. But it was well above normal in Tauranga and also high in parts of Northland and Waikato.

The warm November weather contributed to record dryness in parts of the South Island where several century-old records tumbled. Lincoln had a 35-day dry spell (less than 1mm of rain on any day) and Orari had no rainfall at all during November, the first time that has happened in 120 years.

Cromwell had 12 consecutive days where the temperature was at 25°C or above – with three of those higher than 30°C, which is the most ever for November.

But in Roxburgh in Central Otago, flash flooding on November 26 saw homes evacuated and the town cut off from the south by slips and surface flooding. The town water supply was also cut off. By the last week of spring, soils were significantly drier than normal across large chunks of the country.

Research subject: Climate