For a large part of the afternoon, the city duelled with Waitati (17.3°C) and Timaru (17.4°C) for the warmest temperature of the day in New Zealand, but all three were edged out late in the day when Kawerau (in the North Island) reached 17.5°C at 3.45pm.
Oamaru was "close-ish" with 16.9°C.
Unofficial MetService temperatures showed North Dunedin reached 21.2°C and St Clair Beach reached 20.2°C about 2pm.
And the good news is, there is more warm weather to come.
It was the first time in the past 30 days that the mercury had moved into the high teens.
Before yesterday’s reading, the average July temperature was 10.8°C and the warmest temperature was on July 5, when it reached a paltry 12.8°C.
MetService meteorologist Oscar Shiviti said the relatively warm weather was because of the foehn wind effect, where westerly winds dried out and warmed up as they blew over the Southern Alps.
"At the moment, there is also a high pressure system moving in from the northwest of the country, and it would continue to push in over the next few days as well."
The official MetService record for the hottest July temperature in Dunedin was set in 2004, when the mercury hit 19.8°C.
Yesterday’s warm weather was not shared by other areas of Otago and Southland.
Alexandra, Queenstown and Wanaka struggled to reach double digits, while the rest of the southern region only just made it.
Mr Shiviti urged Dunedin residents to make the most of the winter anomaly as a polar blast was expected to move east on to the west of the South Island on Sunday, along with cold southerlies which may bring snow to "relatively low levels" for much of Otago and Southland — including Dunedin — on Monday, Tuesday and Wednesday next week.
It was still too early to say exactly how low snow would fall or how heavy it would be.
