Last month, New Zealand experienced its warmest May since records began in 1909, according to the National Institute of Water and Atmospheric Researc
Last month, New Zealand experienced its warmest May since records began in 1909, according to the National Institute of Water and Atmospheric Research (NIWA). This marks the fifth consecutive year that May has been among the warmest on record. The nationwide average temperature for May was 13.1 degrees Celsius, which is 2.0 degrees Celsius higher than the average for the period of 1991-2020.
Several regions across the country witnessed exceptionally high temperatures during the first eight days of May. This warmth persisted throughout the month, with temperatures above or well above average in every region of New Zealand. Sea surface temperatures near the South Island were also the second warmest for May since 1981, partly due to a marine heatwave that delayed the transition to colder temperatures.
NIWA attributed the widespread warmth to climate change, emphasizing its exacerbating effect on weather patterns. Additionally, May saw abundant rainfall in many parts of the country, with above or well above normal totals in several regions. Notable rainfall records were set in Kaikohe, Rotorua, and Motueka, while Oamaru experienced particularly dry conditions.
Overall, this autumn ranked as the fourth warmest on record, with an average temperature of 14.5 degrees Celsius, surpassing the 1991-2020 average by 1.1 degrees Celsius. The season also witnessed numerous locations recording their warmest or near-warmest autumn on record, further highlighting the trend of increasing temperatures.
NIWA noted that much of the warmth during autumn was driven by elevated overnight temperatures, with several locations experiencing their warmest mean overnight temperatures for the season. Auckland emerged as the warmest among the six main centers, while Christchurch was the coolest and driest. Tauranga received the highest rainfall and sunshine hours, whereas Wellington had the least sunshine.
As the year progresses, Taranaki, Central Otago, Mackenzie Basin, and the West Coast have emerged as the sunniest locations so far in 2023.