The temperature in Dunedin city dropped only to 19degC on Sunday night, and by 9am yesterday it was 24degC - the hottest place in New Zealand at the time, according to the MetService.
The temperature at the airport dropped to 18degC overnight on Sunday, and was 21degC by 9am yesterday.
The temperature stayed high in the city for most of yesterday, reaching 29degC by 1pm.
The temperature dropped nine degrees by 2pm and then stabilised for the rest of the afternoon.
The forecast for Dunedin for the rest of the week is for strong northerlies and northeasterlies on Thursday before a southerly change on Friday with overnight lows dropping to about 10degC.
The MetService yesterday issued a severe weather watch and warning due to an active trough predicted to move across southern and central New Zealand from last night to tomorrow.
In the east, northwest gales are forecast from Southland to Wairarapa, while in the west heavy rain is expected.
MetService weather ambassador Bob McDavitt said another front on Friday was likely to be followed by a cooler and less humid southwesterly flow.
"The picture for Christmas Day is slowly becoming apparent and we are more optimistic about settled weather than we were a few days ago.
At this stage, we expect fine conditions in eastern districts of both islands, clearing weather in most western districts, but still some showers around the west and south of the South Island."
National Institute of Water and Atmospheric Research climate scientist Georgina Griffiths said Sunday's overnight temperature in Dunedin was not quite as high as the December highest minimum record of 19.8degC, recorded on December 2, 2001.
It also fell short of the December peak afternoon temperature record of 32degC, recorded last Christmas Day, and the Dunedin extreme maximum temperature record of 34.9degC, recorded on February 26, 1995.
Overall, temperatures in Otago have been warmer than normal for the past two months.
