The South Australian capital of Adelaide has set a record for its most summer days of 40 degrees Celsius or more.
The previous mark of 11 had stood for 117 years.
There now have been 12 days so far this summer over 40 degrees, ABC reports.
The Bureau of Meteorology says 20 areas across South Australia have had a record number of days 42 degrees and above.
More extreme temperatures are expected in coming days.