The coldest area in the North Island was Araetihi, in the Whanganui hills, which got down to -1.8C.
Hamilton was 3.7C, Tauranga was a respectable 9.1C and Wellington recorded 9C.
It was a bit different in the deep south. Pukaki, near Mt Cook, plummeted to -6C. Lumsden was -4.6C, Tekapo -3.9C, Alexandra -3.6C, Gore -3.3C and Invercargill -3C.
It was slightly warmer on the coast - Dunedin city and Christchurch got down to 6C.
Clark said the South Island will clear up today and fine weather is forecast for the West Coast.
Conditions could be variable in many parts of the North Island as a front moves west to east, which will bring showers to a few cities including Auckland and Tauranga.
Philip Duncan, of Weatherwatch.co.nz, said although June had kicked off cold there had been pockets of warm air.
However, a large low this weekend could drag in a cold, snowy, southerly especially for the South Island mountains and ranges.
"This time next week another very large high from southern Australia will be drifting towards New Zealand.
"Next week's high may bring in more westerlies and may not be overly cold - not as cold as this week by the looks of it.
"Our feeling is that June will be colder than a year ago with weekly rain events still impacting western and northern areas in particular but also plenty of dry and frosty days as these large highs streaming in from southern Australia and the Indian Ocean continue to track our way."
