Temperatures have soared past 46C in northwestern NSW while thunderstorms have begun to hit southern parts of the state, with winds and lightning increasing the risk of bushfires.
As NSW sweats through the peak of a week-long heatwave, scorching conditions have continued to break records ahead of a cool change expected to sweep the south late Friday.
A small patch of rural NSW has endured the hottest night ever recorded in Australia, with a minimum overnight temperature of 35.9C halfway between Cobar and Wilcannia, at Noona.
"That's an all time Australian record for the warmest night at any time of the year," the Bureau of Meteorology's Ann Farrell told reporters in Sydney on Friday.
Just over an hour away from the tiny community, locals at Cobar said the heat was taking a toll on workers, and power bills, as people struggled to keep cool.
A kitchen thermometer at Cobar's Empire Hotel had repeatedly reached 50C, bar attendant Britney-Lee Fazulla told AAP.
"It's very difficult but we push through," she said.
The 19-year-old, who has lived in Cobar all her life, said it was the worst heatwave she's experienced.
Cobar also recorded its highest ever minimum temperature overnight of 33.2C.
At Tibooburra Airport the mercury climbed to 46.9C, while in the ACT Canberra experienced its fourth day in a row above 40C for the first time since records began.
In Sydney, Penrith reached 41.6C while an earlier than expected sea breeze capped temperatures in the CBD at 29.4C.
Relief is expected in southern NSW Friday night and Saturday, while storms have begun to hit some regions with a warning issued for damaging winds on the South West Slopes and parts of the Southern Tablelands .
"Thunderstorms are happening across parts of southern NSW, bringing the risk of current fires being whipped up and the potential for lightning to start new ones," the NSW Rural Fire Service tweeted on Friday afternoon.
Total fire bans remain in place across much of central NSW, from the Victorian border to Queensland.
Temperatures in some areas will drop by 10C but only a one- or two-degree difference will be felt further north by Sunday.
"Unfortunately, that relief is going to be fairly short-lived, as temperatures will gradually start heating up again," Ms Farrell said.
Heart Foundation NSW chief executive Kerry Doyle reiterated that people should take extra care and keep hydrated, especially the elderly, children and those with heart issues.
