An expected short, sharp shock of cold weather early next week would take some heat out of June, Niwa meteorologist Ben Noll said, but it was expected to be the warmest June in New Zealand’s records.
Snow to low levels was expected to accompany low temperatures and icy winds in the South at month’s end, but several Otago towns were recording temperatures well above average this winter.
Wanaka was on track to record its warmest June, and Dunedin (second warmest), Oamaru (third), Queenstown (fourth), Alexandra (fourth), and Roxburgh (fourth) were among 80 locations across New Zealand tracking towards a record, or near record, June, Mr Noll said.
Up until June 20, the nationwide average temperature was 10.97degC, much higher than the long-term average of 8.59degC.
Warmer than average temperatures over the western Pacific Ocean were a factor.
Low pressure systems from the north had brought rain to the North Island and the east coast of the South Island, but there had been warmer than average air temperatures.
Further, a lot of the cold air that built up over the winter season had been ‘‘trapped’’ over the Antarctic by a strong polar vortex, Mr Noll said.
The swirl of wind and storms tended to keep cold air close to the South Pole and had been quite efficient at keeping it there so far this winter, he said.
Niwa research had shown New Zealand winters to be consistently shorter than they used to be.
There was a ‘‘climate change handprint’’ in the warm weather this month as well.
‘‘In a warming world it doesn’t mean that you can’t get cold temperatures during winter, but what it does mean is that the likelihood that you’ll have extreme cold, and extreme cold that lingers for a long time, is lower,’’ Mr Noll said.
‘‘We’re certainly at some level feeling the effects of climate change underpinning all the things that we’ve talked about here.’’
