Large swaths of south-east Australia continue to swelter under extreme heat, with the mercury above 40 degrees at lunchtime in Melbourne and Adelaide.
Many NSW residents are tipped to cop temperatures in the 40s, while Tasmanians also sweat through hot weather.
Melbourne suffered through a 41-degree-plus day on Wednesday, which was the second of four days predicted to be above 40.
If that happens, it will be the first time the city has endured such a heatwave since 1908, when there was a five-day streak over 40 degrees. At 1.30pm, the temperature in Melbourne was 41.5 degrees, with Charlton, in the Mallee, recording a scorching 42.9 degrees.
Melbourne's weather was so hot that at the Australian Open on Tuesday a player hallucinated that he saw Snoopy on court before fainting mid-match, a ball-kid collapsed and water bottles melted on court.
A total fire ban is in place for the state, and the Victorian government issued a heat health alert, urging people to stay hydrated and check on the elderly.
Across the border, Adelaide was the hottest of any capital city, recording 42.4 degrees at 1.50pm.
Adelaide faces temperatures above 40 degrees for the next five days, as does most of the state including Renmark and Port Augusta.
The state's hottest weather on Wednesday was at Roseworthy, near Gawler, at 42.6 degrees.
Extreme heat warnings have been issued by South Australia's State Emergency Service until Thursday.
The temperature hit a mild 19.3 degrees in Hobart, but a total fire ban is in place for the state's northern and southern regions.
In those regions the state's temperatures were into the 30s, well above average even for summer. The town of Ouse, in the upper Derwent Valley, was the hottest part of the state at 34.8 degrees.
In NSW, Sydney was spared super-hot weather thanks to a coastal sea breeze that kept the temperature under 30 degrees.
However, it was much hotter in the city's west, with the bureau expecting the mercury to reach 39 degrees at Penrith. The bureau warned people not to expect a cool change until Saturday.
Large parts of the state are suffering extreme heat, with the town of Deniliquin, in the Riverina, tipped to record a number of 44-degree days.
Swan Hill recorded NSW's hottest temperature for Wednesday with 43 degrees.