With five days to go until the official end of winter, many Otago centres, including Dunedin, have so far recorded record-breaking average temperatures.
Niwa figures show it has, so far, been the warmest winter in 66 years at Dunedin's Musselburgh station, in 105 years in Oamaru and 89 years in Alexandra.
It has also been one of the wettest winters so far for Central Otago, with Lauder recording its highest winter rainfall since 1924, Alexandra its highest since 1983 and Cromwell its second-highest.
Niwa climate scientist Andrew Tait said it would not be until early next week, when all of the data for August would be available, that records could be talked about. A change in weather could mean the difference between a record-breaking figure and a second-warmest temperature.
MetService meteorologist Dan Corbett said the glorious weather and 15degC-18degC temperatures would come to a brief halt on Thursday as a cold southerly brought rain and sleet to the coast and snow inland, although temperatures were still expected to reach 11degC.
''It'll be a sharp change.''
It would start to ease back on Friday with a high bringing frosts and sunny, but cool, weather for the first days of spring.
Hydrologist Dave Stewart, of Dunedin, said the figures also obscured the fact that June was average for temperatures and also very wet, while July and August had been dry and warm.
''It's definitely been warmer than usual and, even if we get the rain forecast for later in the week, it'll be a well-below-average rainfall month again.''
When the figures were pulled together as ''winter'' data, it was wetter and warmer than usual, he said.
What this meant for spring and summer was up for debate. Many pessimists believed the cold winter could still arrive, he said. September and October could often be cold and wet.
''I hope we do not pay for this [warm winter] with a bad summer.''
The warm weather had allowed the ground to dry out after June's downpours and the warmth since had brought on early grass growth.
Farmers would now be looking for ''a good soaking'' before the September winds, Mr Stewart said.
''They're absolutely delighted but they'll be suspicious and wary of what is to come.''
