There has been more fog than usual in Auckland this year - and that is likely to continue through winter, the MetService says.
Fog caused about 50 flights to be delayed or cancelled at Auckland Airport this morning, the third time fog has hit the airport in three weeks.
Auckland Airport said although the fog had since lifted, delays continued.
For flight information, check Auckland Airport's website.
Severe weather forecaster Erick Brenstrum said the heavy rain that battered the North Island over the last six months was likely the culprit.
"In places it's been the wettest period they've [Auckland] had, that makes the ground water quite high and that's one of the ingredients that makes fog," he said.
Mr Brenstrum said clear skies, light winds and a lot of moisture in the ground was a recipe for fog and Auckland Airport may see more disruptions as the country heads into winter.
"This phenomenon is ... mostly happening over the top half of the North Island and in other parts of the country it's just a normal year for fog," he said.
Winter was also being felt in parts of the South Island, with freezing temperatures recorded.
MetService said just after dawn today it was -3°C at Dunedin Airport and in Invercargill, and -4° in Alexandra and Gore.
The Transport Agency said there was a risk of ice on the roads, with ice already reported in Kawarau Gorge to Gibbston near Queenstown and on State Highway 87 from Kyeburn to Outram north of Dunedin.
A frosty morning for the south - low cloud spared Chch & Dunedin from colder overnite lows. Lowest temp recorded was in Pukaki at -6C ^AC pic.twitter.com/Y4HeEcH42L— MetService (@MetService) June 5, 2017