A change in wind direction has sent Northlanders grabbing extra sheets and layers of clothing but the good news is an early spring will usher in warm weather in a week or two.
WeatherWatch senior analyst Philip Duncan said a change from northerly to southerly winds brought overnight temperatures in Northland to as low as 4C while the daytime temperature was around 17C.
"In June/July there were a lot of subtropical lows and a number of southerly winds flowing out of the subtropics but halfway through July and early this month the wind direction changed to southerly," he said.
"Northlanders are feeling more cold than other places because you've had an exceptionally warm June and July but this cold should last another week or two."
Clear skies during the day enabled heat to disappear and resulted in cooler nights.
"The worst of winter is over. The days are getting longer by at least 15 minutes and I believe we'll have an early spring."
There was still a possibility night temperatures may fall further, bringing the odd frost and cold snaps but that was unlikely.
Kerikeri Airport was the hottest place in the country on Sunday at 15.7C while Whangarei Airport and Whangaparaoa were joint second with 15.2C. Rain is forecast for Whangarei and Kerikeri today but fine weather is predicted for the rest of the week.