The Mackenzie Basin has taken the crown as the country's sunniest spot. Photo: Unsplash / Sébastien Goldberg
2023 was New Zealand's second hottest year on record and among the cloudiest, NIWA has announced.
Globally, last year has been confirmed today as the warmest year on record but in New Zealand the record belongs to 2022.
The weather research agency said 2022 was just slightly warmer, and 2021 was a close third.
Data released on Wednesday by the National Institute of Water and Atmospheric Research shows its seven weather stations recorded eight months of above-average temperatures in the past year.
May and September were the warmest, coming in 2 degrees Celsius above the 1991-2020 monthly averages. Principal scientist Chris Brandolino said that result was "astounding".
"[It] was a record warm May for the country ... The winter season ended up being the fifth warmest on record, September was the warmest on record," he said.
August was relatively cool with below-average temperatures.
"Something happened in 2023 that hasn't happened in more than six years, we had a below average month," Brandolino said.
"August 2023 was the first time since May of 2017 where Aotearoa observed a colder than average national mean temperature."
The hottest day was recorded at Middlemarch on 4 February at a scorching 35.6C and the coldest was recorded at Tara Hills near Ōmarama at -10.6C.
The sunniest spot was not in Whakatāne or Nelson, as is often the case, but the Mackenzie Basin at Lake Tekapo with 2658 hours of sunshine throughout the year.
Coloured stripes showing a time series of the national temperature anomaly calculated from NIWA's Seven Station Photo: Supplied / Niwa
Series, relative to the 1991-2020 baseline. Red colours indicate temperatures above the 1991-2020 baseline while blue colours indicate temperatures below the baseline.
Of the six main centres in 2023:
- Tauranga was the wettest and sunniest
- Dunedin was the driest
- Auckland was the warmest
- Christchurch and Dunedin were equal-coolest
- Wellington was the least sunny.
The year was also the fourth cloudiest on record. To determine this NIWA used solar radiation data stretching back to 1972. It showed the nationwide solar radiation anomaly was 97 percent of normal, meaning more clouds.
Very wet but also very dry
Flooding near Waimauku in the Auckland region. Photo: RNZ / MARIKA KHABAZI
Rainfall broke records in Auckland during the Anniversary Weekend floods.
"January 2023 was the wettest month ever, of any month, on record in Auckland," Brandolino said.
"Albert Park [recorded] 538.5mm of rain... records at Albert Park extend back to 1853."
The wet weather continued into February with Cyclone Gabrielle driving torrential rain in much of the North Island.
"There were areas in the North Island that received more than a third of their annual rainfall in just one day," he said.
Despite that, droughts in the South Island meant 2023 was only the 21st wettest year on record.
"2023 was certainly a year of extremes," meteorologist Ben Noll said.
"Whether it was flooding, rain, droughts and record temperatures. We had everything mixed into one year."
Annual rainfall anomalies as a percentage of the 1991-2020 normal based on data from NIWA's network of virtual climate stations. VCSN rainfall data has been collected since 1961. Photo: Supplied / Niwa
The West Coast experienced significantly less rain than normal although the country's wettest locations were also in that region: Cropp River at 11,717mm, Tuke River at 10,454mm and Hokitika at 8250mm.
The highest rainfalls recorded in a day were 565mm at Castle Mount in Southland on 16 September and 561mm at Tareha (near the Esk River in Hawke's Bay) on 13 February.
The lowest recorded rainfalls were at Ranfurly with 359mm, then Alexandra with 361mm, followed by Cromwell with 404mm.
Noll expected the extremes to continue.
"It's kind of a dress rehearsal for the future, what things will be like in 2030, 2040 and 2050 as we continue to travel in this direction," he said.
A different El Niño
Chris Brandolino Photo: SUPPLIED
The weather patterns of 2023 and into this year have been dominated by the shift from La Niña weather patterns in the first half of last year to El Niño in the second half.
"This isn't your parents' or your grandparents' El Niño," Brandolino said.
Previous El Niño patterns had seen warmer ocean temperatures coming off South America with patches of cooler water in the surrounding Pacific Ocean.
But in 2023, the Pacific experienced "an absence of cooler ocean temperatures", he said.
"This is very different from years past."
This meant the impacts of El Niño were exacerbated.
'Eye opening' rainfall for Auckland
Brandolino hoped people wouldn't become acclimatised to the constant breaking of records.
"I hope it doesn't become white noise, all these record years. I hope people think about what is happening," he said.
Aucklanders had lived through extraordinary rainfall during the Anniversary Weekend floods, he said.
"It was eye-opening. We lived through it. Then there was Cyclone Gabrielle. We saw it coming. It had profound impacts on people."
NIWA's annual report states: "Climate change continues to influence New Zealand's long-term temperature trend, which has warmed at a rate of approximately 1.17 degrees Celsius (±0.2degC) per century according to NIWA's seven-station series."