Down the motorway at Hamilton International Airport a meagre -1 degrees was reported at 6am, while it was 4.1 degrees at Wellington International Airport and 2.4 degrees in Lower Hutt.
Glassey says those overnight temperatures are pretty cold for the Wellington region as there's usually a bit of wind in the mix to make the ambient temperature slightly warmer. The less wind overnight the colder it will get.
Christchurch International Airport recorded 0.2 degrees while down the road at Dunedin Airport it clocked up a chilly -1.3 degrees.
Dunedin is also currently hidden under a bed of fog but Glassey expects that to burn off by about 9.30am or 10am because now that we're in September the sun had a bit more power in it.
But the coldest overnight temperature goes to the Central Plateau with -5 degrees recorded on the Desert Rd.
It is going to warm up today though. Auckland, Hamilton, Christchurch and Dunedin will all reach highs of 16 degrees, while Wellington will remain a bit cooler on 12 degrees.
However, Glassey says now that the cold has front has passed, the country can expect warmer temperatures.
As for rain, today will be mostly fine across the country, however a weak front will hit the lower western side of the South Island bringing unsettled showers and rain late today or tomorrow.
That weather isn't expected to hit the North Island until Wednesday or Thursday and even then it will be patchy.
However, by Friday a "more significant front" will hit the country bringing wet weather but temperatures are not expected to drop.
"It's a little bit messy I guess for the first part of the week, quite a slow moving, weak feature. The idea is that the temperatures are returning to normal after the cold snap we had at the end of last week."