It can be bloody inhospitable, that's why 95% of the population ives on 5% of the land here.

Hottest recorded temperature was Oodnadatta here in South Australia at 50.7C

The next from Wikipedia: (It is out of date though as we had 47C here in Jan 2019)

"The most powerful heatwave in the history of south-eastern Australia occurred in January 1939. Adelaide (46.1 °C on the 12th), Melbourne (45.6 °C on the 13th) and Sydney (45.3 °C on the 14th) all had record-high temperatures during this period, as did many other central district areas in New South Wales, Victoria and South Australia. The record number of consecutive days in Melbourne over 40 °C is five, with Brisbane and Sydney each having two. Heatwaves usually bring by oppressively warm nights, with Oodnadatta, SA recording an Australian record of nine nights above 30 °C in February 2004.[73] Another extreme event was a prolonged period of extensive heatwaves known as the Angry Summer in early 2013."

"Marble Bar achieved 160 consecutive days above 37.8 °C (100.0 °F) in 1923–24. Nyang had an average maximum of 44.8 °C for the months of February 1998 and January 2005, an Australian record. At the other extreme, average January maximums are near 15 °C on the highest peaks of the south-east ranges and near 20 °C in much of Tasmania. In most of the desert region during summer, cool days are rare and usually associated with major rain events—a rather exceptional example occurred in February 1949, when many areas failed to reach 20 °C on one or more days, and the maximum at Boulia, western Queensland was at 14.4 °C, which was 23 °C below normal."

See link.

https://en.wikipedia.org/wiki/Climate_of_Australia