In the North Island, inland parts also felt the freeze the worst, with Taupo Airport dropping to -4 degrees Celsius overnight.
Paraparaumu Airport on the Kapiti Coast fell to 0 degrees, while in Auckland Whenuapai Airport dropped to -1 degrees Celsius and Albany dropped to -0.3.
Mr Gall said the frosts were not unusual for this time of year.
"We're comparing it with what has been a fairly gentle winter. It was a little bit warmer, we've had a fair bit of rain in places but it wasn't all that cold. But cold outbreaks are possible any time. You'll see a few decent cold outbreaks during most springs. The danger is this is the time when buds are budding and fruit trees are trying to set themselves up.
"We should be getting warmer temperatures. We may see some more frosts tonight, especially over the North Island where the wind hasn't quite started up yet. But the South Island will be warmer up because we've got a northwester blowing across it and that will be steadily increasing today."
- nzherald.co.nz