not the whole country - the areas affected are inland, mainly in South Australia Bureau of Meteorology

news article published 2 days ago - 'Like a furnace': Massive heatwave could roast Australian records Almost all of mainland Australia will be roasted in a huge heatwave next week, with the mercury likely to nudge 50 degrees in parts of the south ....
On present forecasts, the hottest places may be in South Australia, with the Bureau of Meteorology indicating back-to-back days of 49 and 50 degrees in some remote regions for next Wednesday and Thursday ...
Much of the country's south will exceed 45 degrees by midweek, or 12-16 degrees above the December average, she said ...
Melbourne and Sydney will most likely be spared the worst because of sea breezes, but inland suburbs might still swelter ...
In Sydney, updated forecasts have the city reaching 33 degrees on Thursday while western suburbs such as Penrith could reach 44 degrees, the bureau said ...
The hottest December day was marked in Birdsville, Queensland, on Christmas Eve, 1972, with a 49.5 degree reading ...
Two of Australia's only three reliably measured temperatures above 50 degrees were recorded at Oodnadatta in South Australia, with 50.7 on January 2, 1960, and 50.3 the following day. Mardie in the WA's Pilbara hit 50.5 degrees on February 19, 1998. Oodnadatta is forecast to reach 46-47 degrees for the three days from Tuesday, while Mardie is already in the midst of at least eight days at least 40 degrees.