Niwa brands 2017 a ‘year of extremes’
New Zealand has experienced its fifth-warmest year in more than a century in a 12 months marked by extreme weather.
Niwa yesterday released its annual climate summary for 2017, saying it had been a “year of extremes”.
Annual rainfall was above normal across the country and in some regions, including Auckland, Waikato, Bay of Plenty, coastal Canterbury and north coastal Otago, as much as 149 per cent higher.
It was an especially wet year in Oamaru, which had its secondwettest year on record — 813mm of rain — and its wettest winter.
On July 21 a whopping 161mm of rain fell, making it the wettest day in the town since records began in 1950.
At the same time the country had higher-than-usual temperatures, making 2017 the fifth-warmest year since records began in 1909.
January was the only month when temperatures fell below average with six months recording above-average temperatures. April, August, September, October and November were all between 0.7C and 1.3C above average, with December 2.4C above average.
While sunshine was near normal across the country, Nelson was the sunniest region with 2633 hours of sun.
Niwa described 2017 as a year of two halves. The year started off on a wet and stormy note across the South Island in January before reaching record or near-record rain- fall and flooding across the North Island during the “Tasman Tempest”, ex-Tropical Cyclone Debbie and exTropical Cyclone Cook which swept through in March and April.
Later in the year, parts of the western and lower North Island were in a meteorological drought as very dry weather in November led to major decreases in soil moisture.
Niwa said Christchurch observed just a single millimetre of rain during November, the driest November on record. The city had a 47-day dry spell that was broken in mid-December.
Sea surface temperatures also fluctuated, starting the year at normal levels but reaching up to 4C above average as a “marine heatwave” hit coastal waters in November and December.