A cyclone is brewing off Western Australia's Kimberley coast while much of the country is set to swelter in heatwave conditions.
Every state and territory will cop the heat on Monday when temperatures soar with some regions to experience severe and extreme hot weather.
The Bureau of Meteorology forecasts low intensity heatwave conditions in parts of central WA to southern parts of the Northern Territory, southwestern Queensland and across NSW, Victoria, Tasmania and South Australia.
It will be worst in South Australia where multiple days of temperatures above 40C, an unusual event even for summer, meteorologist Dean Narramore said on Sunday.
"Particularly northern South Australia, they're looking at maybe five days in a row above 45 and normally they might only get five or 10 a year," he said.
Melbourne can expect to see a few days in the mid to high 30s, while temperatures in Sydney's west will peak above 40C for four or five days.
