Alexandra and Middlemarch claimed the regional high, both topping 30degC.
MetService meteorologist Tom Adams said temperatures were likely to stay in the mid-20s for most areas for the next couple of days but it would be coupled with some patchy showers for Dunedin.
''[It is] quite warm today because we've got this northwesterly coming in ... and [it's] dropping all this moisture on the West Coast.''
By the weekend it ''wouldn't be this hot'' as the air mass moved on, Mr Adams said.
Dunedin Airport reached a high of 28degC while Queenstown and Oamaru both got to 26degC.
Balclutha was 25degC.
Christchurch recorded the country's high of 33degC, Mr Adams said.
Today, Dunedin Airport was forecast to reach the region's high of 26degC.
Dunedin city, Alexandra and Oamaru were forecast to get to 25degC, Balclutha 23degC and Queenstown 20degC.
