Winter is one month shorter

Climate change has slashed the length of New Zealand winters by a third, Niwa data shows. The discovery shows on average our three-month winters have decreased by 30 days to two months.

‘‘If this trend continues we eventually won’t have winters anymore,’’ Niwa principal climate scientist Dr Brett Mullan said. The country’s average winter temperature has jumped the rails, up by 1 degree Celsius compared to 80 years ago.

‘‘This is a consequence of rising temperatures around the globe, and such trends in colder temperatures and frosts will influence the life cycle of plants and animals,’’ Mullan said. ‘‘The figures showed that, if a threshold of 9 degrees Centigrade was chosen, then there was an average of 100 days per year between 1909 and 1938 when the temperature was less than 9C, compared to only 70 days per year between 1987 and 2016.’’

Climate scientists consider 30 years to be the minimum amount of time to come up with a statistically meaningful longterm average, he said.

‘‘Winter has contracted about equally from both ends.’’ By 2050 there may be no winter as we now know it, he said.

Compared to the North Island, the South Island will experience dryer summer conditions.

Winter’s length will continue to fluctuate because of factors including varying predominance between opposite cycle El Nin˜ o and La Nin˜ a weather patterns.

Niwa has forecast a 70 per cent chance warmer, wetter La Nin˜ a weather will boost 2017/2018 summer temperatures.

The Royal Society’s 2017 Climate change and health report said climate change ‘‘threatens’’ New Zealander’s ‘‘health and well-being’’.