The hottest day is forecast for Saturday, with Sydney to bask in 27 degrees, Melbourne 26 degrees, Canberra 25 degrees and Adelaide 24 degrees.
But some parts – such as Western Sydney and inland NSW and SA – will see the mercury climb higher to 30 degrees plus.
Forecasters also believe Saturday will be the warmest September day since at least 2021 for those areas.
And the heat will hang around on Sunday, September 17, when thousands of runners take part in the Sydney Marathon event.
Temperatures of 17 degrees to 19 degrees are expected for the start of the races and will warm to a top temperature of about 28 degrees during the early afternoon.
The warm sunshine will be welcome after the mercury plunged over past days.
Last Friday, Melbourne’s maximum of 11.7 degrees was its coldest September day since 2004, while Adelaide’s 13.4°C was its coldest for September since 2018. Neither capital city felt above single digits all day.
(9 NEWS)
