It was a chilly -11.6C at Mt Cook Airport on Saturday night – the coldest temperature recorded by MetService this year.
That’s just a little colder than the registered -11C by MetService at a station near Ōmārama on June 22, and the -11.2C recorded by Niwa Weather in Middlemarch on June 23.
Canterbury residents also woke up to a frosty morning. Christchurch Airport dropped to -5.5°C between 5am and 6am on Sunday, the coldest temperature at that station in 2022 and the eighth coldest of the stations used by MetService at night.
At Aoraki/Mt Cook, temperatures dropped between 11 p.m. and midnight on Saturday, then rose significantly by 1 a.m. Sunday, when strong northwesterly winds came through, MetService meteorologist Tui McInnes said.
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The lowest temperature between midnight and 1 a.m. was -10.2C, but during the 10 minutes of 12:50 a.m. and 1 a.m. the average temperature was 3.1C.
“It’s quite a big difference,” and it happened quickly, McInnes said.
George Empson/delivered
A western arc over Tekapo on Sunday. Temperatures in the Mackenzie fell to record lows on Saturday night, with a record at the Aoraki/Mt Cook airport of -11.6°C.
The main reason the airport had become so cold was because it was completely snowed in.
“The coldest temperatures occur in the days after it snows. The snow acts like a big mirror for the sun’s radiation,’ said McInnes.
Robyn Edie / Stuff
Christchurch had a frosty start to Sunday, with temperatures dropping to -5.5C between 5 and 6am (file photo).
Much of the heat in the atmosphere was created by the land absorbing solar radiation and then reradiating it at a different wavelength.
“When it snows, you don’t come close to the same absorption level.”
Some other cold temperatures recorded overnight were -7.7C at Tekapo, -8.4C at Pukaki Airport and -9.1C at Burkes Pass.
Omarama hot tubs/provided
The ice sculpture in Ōmārama after the temperature there dropped to -11C in June.
In Christchurch, the cold temperature was largely the result of mostly clear skies and little wind, McInnes said.
“It looks like cold air is being dragged over the area.”
Temperatures did not reach double digits on either Friday or Saturday and dropped rapidly on Saturday evening once the sun set.
It was 9 degrees on Saturday at 5pm and by 8pm it had dropped below 0 degrees. “The sun disappeared and so it cooled down.”