Mount Gambier has equalled the record for its longest stretch of hot weather.
The temperature reached 39.7 degrees yesterday, making it 11 days in a row above 30 degrees - equal to the record set in 1956.
Mount Gambier also recorded nine nights of temperatures above 15 degrees, beating the record set in 1983.
In Robe, 10 days above 30 degrees has also beaten the record of seven days.
The Bureau of Meteorology's Darren Ray says a cool change is due to reach the region overnight.
"It has been a particularly prolonged period of heat with the high-pressure system sitting out in the Tasman Sea for about the last 12 days or so," Mr Ray said.
"That has been directing a north-easterly airstream over south-eastern Australia, so that's stopped Mount Gambier from getting those south-easterly coastal winds that often break up the heat in summer and into early autumn."
Mr Ray doubts Mount Gambier's heat records will be broken.
"That means the temperature on Wednesday is going to be much cooler, back in the low 20s rather than in the mid 30s," he said.
"That will actually break this record stretch of hot weather and that's looking like we will see cooler conditions continue certainly for the next week or so."
© ABC 2013
14:55 EDT Tropical lows in the Gulf of Carpentaria and Coral Sea could intensify into tropical cyclones tomorrow morning before possibly making landfall on Monday morning.