Frost-fighting helicopters were expected to be out in force in Marlborough before dawn again this morning as viticulturists try to save their vines.
Temperatures were forecast to drop to an air minimum of 1C with a minus 2C frost in inland areas of the grape-growing province.
The frosts are the sting inthe tail of the wintry blast that dumped snow in the southern parts of the South Island and rain in the north.
An anticyclone yesterday gave authorities the opportunity to clear roads of snow - and although temperatures were cool, most of the South Island was treated to a day of brilliant sunshine.
Otago high-country farmers were yesterday starting to count their losses after thousands of newborn lambs succumbed to the harsh weather. Deep snow stopped farmers getting near lambs born on Friday and Saturday and they died in the snow.
More than 20 helicopters were hovering over southern valley vineyards yesterday when the first frost hit.
Wither Hills viticulturist John Marris said the freeze was a dangerous frost that threatened chardonnay and pinot noir vines with new leaves emerging.
Marlborough grape growers, wary after November frosts last year wiped out 30 per cent of their grape harvest, were quick to respond to frost forecasts on Sunday afternoon by preparing frost protection, including the helicopters.
Mr Marris measured temperatures as low as minus 2.5C yesterday, but said a helicopter running from 4.20am "saved the day".
The danger period for vineyards was between now and November 22, he said. The first three weeks of November were the highest risk period, when leaves and shoots were more advanced.
