Temperatures have reached a scorching 46C in northwest NSW as the rest of the state sweltered, but conditions aren't expected to ease soon with higher maximums forecast for Friday.
Bourke sweltered as the mercury maxed out at 46C shortly before 3pm while parts of western Sydney topped 40C on Wednesday.
Tourists are avoiding the outback town, which is on the fringe of a desert, and they're unlikely to return soon with the forecast temperature predicted to reach a blistering 47C on Friday.
For those that do intend to stay around, publican Tracey Hegartey from the Port Of Bourke Hotel has some straight advice.
"Mate, just stay cool and drink plenty of beer," she said.
At Penrith, where overnight temperatures didn't drop below 23C, the hot streak continued.
It was one of the warmest parts of Sydney with the Bureau of Meteorology recording 42C in the mid-afternoon.
Bankstown, Campbelltown, Homebush and surrounding areas all copped high temperatures above 40C.
Meanwhile, a severe thunderstorm warning has been issued for coastal parts of the state's north, with damaging winds and large hailstones expected to impact Grafton, Coffs Harbour, Port Macquarie and Tenterfield.
"Stay indoors away from windows, and keep children and pets indoors as well," the SES advised.
A total fire ban has been declared for much of the state, including the greater Sydney and greater Hunter regions due to strong winds and higher temperatures.
Vegetation has dried out considerably, particularly in western NSW, and there's low humidity and winds are up, a Rural Fire Service spokesman said.
NSW Health is also urging people to phone their elderly friends, neighbours and relatives at least once a day and eat smaller cold meals such as salad and fruit.
"The best way to reduce the risk of heat-related illness is to drink plenty of water and keep your body as cool as possible, and avoid prolonged sun exposure by staying indoors in cool or air-conditioned facilities," the Bureau of Meteorology (BOM) said in a statement.
The forecast is for cooler conditions on Thursday, but it will be small consolation for the state's west where temperatures are again set to hit the mid-to-high 40-degrees on Friday.
