In the North Island, Auckland would fall to a minimum of 6C overnight, with Hamilton dropping to 3C and Wellington sinking to 7C.
Napier would slip to a low of 4C and Tauranga was set for a minimum of 5C.
Hayes said lows in much of the South Island would be below 0C.
“Minus 2C for Christchurch, -2C for Invercargill and looking at -5C in Mackenzie Country and -3C for Queenstown,” he said.
Hayes said the nice but cold weather would continue on Wednesday.
Auckland is forecast to reach a low of 8C while Hamilton is set to dip to 1C.
Wellington is tipped to drop to 7C and Napier appears set for a low of 2C.
In the South Island, Christchurch is forecast to fall to 0C, Queenstown to 1C and Dunedin temperatures will reach a low of 6C.
Hayes told the Herald a weather system would approach the South Island on late Wednesday, sweeping across the rest of the country on Thursday.
“Rain or showers [would be] arriving for most of the country,” he said.
“[There will be] continuing showers for most places, possible heavy rain for the west coast of the South Island on Thursday.”
He said showers would linger for most of the country on Friday for Matariki.
“The east coast of the North Island, possibly down to Christchurch, would possibly remain dry.”
