The institute says a warm air mass from Australia will make it feel more like summer for some areas on Thursday and Friday.
O’Connor said the coldest temperature registered at Auckland Airport overnight was 6.1C, around 6am.
That was well below the October average of 11C but still warmer than the airport’s lowest-ever October temperature of 2.4C, recorded in 1994.
The outskirts of Auckland were seeing even lower temperatures, with Whenuapai at 2.3C and Ardmore down to 1.9C this morning.
In the South Island St Arnaud, a tiny settlement in Nelson Lakes, was down to 3.8C while Timaru was at 1.6C this morning.
Meanwhile, the balmiest spot in the country was in the far south, with Invercargill hovering around 12C after dropping to 6.2C last night.
Clear skies in the north were driving the temperature difference, with the North Island lacking a blanket of cloud to hold in the earth’s heat, O’Connor said.
With an area of high pressure sitting over the country some eastern areas of the South Island would be heating up today, with Ashburton likely to be New Zealand’s hottest spot at 25C.
Timaru and Christchurch could also get to 22C and Invercargill would be in the low 20s.
Auckland was likely to see temperatures of 16-18C today.
