The coldest night of the year so far
Last night temperatures for many major centres hit the lowest seen so far this year. Although no long-standing records
were broken, the cold snap would have got heat pumps fired up from Auckland, which dropped to 1.4C at the airport, the
coldest seen since July 2015, to Mount Cook airport, where snow on the ground enabled the second night in a row below
-13C.
The cause of the low temperatures was a ridge of high pressure over the country, meaning clear skies and light winds.
The coldest locations were ones still holding onto a covering of snow from the middle of last week, when extensive snow
fell in inland Canterbury, but also a few flurries as far north as the Desert Road. “A covering of snow reflects the
sunlight away from the ground, but still allows heat to escape”, explained meteorologist Tom Adams, “meaning the ground
cools further each day, chilling the air at night”. A weather station near Tekapo measured -12.0C overnight Fridaynight,
and -11.8C on Saturday night, and only crept up to -0.4C during the day between them. Pictures on twitter have shown the
shoreline of the lake freezing over.