In New Zealand’s Central Otago, wind machines and helicopters are being used to protect precious crop from frosts. Tim Jones, chief executive of 45 South Orchard and Packhouse in Cromwell, says the cold is expected to stick around for another month. "NIWA has got some news out there that this could be a challenging spring," he told Newshub.

A vortex of "stormy and freezing weather" from around Antarctica eventually lets cold air from the south rush north. The last time this happened -in 2002- New Zealand suffered temperatures that were, on average, between 2C and 3C colder than normal.

Jones also said he remembers that challenging spring well. "The last one in 2002 I do recall had an awful lot of frosts right throughout the spring," he said. "Particularly leading on into October and November.Who knows whether we're up for that again this year, but the key thing is that we're prepared for it."

Frost-fighting efforts are cranking up in central Otago to preserve the buds of millions of dollars’ worth of fruit. Forecasters say the central Otago region plummeted to -5C on Tuesday morning.