New Zealand saw second-warmest year on record in 2023, says NIWA

New Zealand experienced its second-warmest year on record in 2023, the National Institute of Water and Atmospheric Research (NIWA) says.  

The institute's annual climate summary showed last year's average temperature of 13.61C fell just below 2022's 13.76C but was ahead of 2021's 13.56C.  

New Zealand's three warmest years have all happened in the past three years and the "clear warming trend observed both locally and globally is consistent with human-caused climate change", NIWA said. 

May and September both recorded the warmest average temperatures on record, above their 1991-2020 averages by 1.1C and 2C respectively.

"Several climate drivers came together to produce an exceptional year of weather in New Zealand," NIWA said.

One of those drivers was La Niña pattern trasitioning to El Niño, which usually caused dramatic temperature swings. 

Climate warming in New Zealand comes amid temperature records across the world that were broken in 2023. This week, the EU's climate service said last year was the world's hottest by some margin.

In December, a global climate deal has been struck at the COP28 summit in Dubai - taking direct aim at fossil fuels for the first time. But critics said the deal was watered-down and not enough.

For New Zealand, hot and dry conditions in the South Island last January as well as above-average temperatures for eight out of 12 months in 2023 contributed to the record, NIWA said.

Christchurch and Stewart Island were among the areas that had their warmest years on record in 2023 while Taupō and Napier had their second-warmest.

Rainfall was also well above normal for Northland, Auckland, Coromandel, Gisborne and Hawke's Bay.

"The past year will be widely remembered for the series of extreme rainfall events that occurred. Starting with the Auckland Anniversary Floods, during which over 200 mm of rainfall fell in a 6-hour period in Auckland," NIWA said.

"Around two weeks later, Ex-Tropical Cyclone Gabrielle unleashed torrential rainfall across the North Island, with some stations near the Esk River reporting over half a metre of rainfall within 24 hours.

"Auckland experienced its wettest year on record, largely due to several extreme rainfall events at the beginning of the year."