Brutal Australia Day heatwave is about to hit: here's how hot your city will get

The heat will continue across much of central and eastern Australia before a cool change sees temperatures drop by as much as 15 degrees this weekend.

Heatwave conditions are expected to persist before a southerly change brings cooler air and relief from the heat for the weekend.

Large parts of central and eastern Australia are in for another hot day after Thursday saw widespread temperatures above 40 degrees Celsius and some inland areas reaching 50 degrees Celsius, including a scorching 49.4 degrees Celsius in the tourist town of Birdsville in Queensland.

A southerly change beginning Friday afternoon will drop temperatures across the region by 10 to 15 degrees.

Australians are celebrating the country's national day despite a heatwave causing temperatures above 40 degrees Celsius in many areas

The heat hasn't stopped Queenslanders from celebrating. Many went to the parks for the traditional BBQ

But before the cool change hits, Sydney will be sweltering, with some areas reaching 40 degrees Celsius by lunchtime.

As the heat continues to move further east, the NSW coast will become a little warmer, with Newcastle and Taree both forecast to reach 41 degrees Celsius, while Grafton and Gosford will reach 40 degrees Celsius.

Temperatures in towns across the Hunter, including Cessnock, Scone and Singleton, are also expected to rise 1-2 degrees Celsius on Thursday, with Singleton expected to peak at 43 degrees Celsius and Scone 41 degrees.

The lower and upper west of the state will once again bear the brunt of the heat, with Bourke reaching 44 degrees Celsius and Moree 42 degrees Celsius.

Thunderstorms are possible in parts of the state in the afternoon and evening.

Sydneysiders will experience more temperate weather on Australia Day and beaches were packed early Friday morning (pictured by Bondi)

Sydney should see good beach weather throughout the bank holiday long weekend

Inland north and south-west Queensland in South Australia will also be warm, but significantly less than on Thursday, where temperatures were around 40 degrees.

South Australia will be noticeably cooler with temperatures dropping around 10 degrees Celsius and Adelaide predicts a high of 24 degrees Celsius.

Heatwave conditions in parts of western and inland Queensland are expected to persist, although most regions will experience a welcome drop in temperatures.

Brisbane is forecast to reach a high of 33 degrees Celsius and the Gold Coast 35 degrees Celsius.

Cooler air spreading across the southern and eastern states will cause temperatures to drop noticeably late Friday afternoon.

The change in weather forecasts will bring cooler weather to almost all areas this weekend.

In Sydney, the Muggera dancers performed a smoke and cleanse at the WugulOra morning ceremony at Barangaroo Reserve, with NSW Premier Chris Minns speaking at the event

“We haven't seen these temperatures for years,” senior meteorologist Gabrielle Woodhouse told AAP.

'Minimum temperatures will also be very warm at night, so there will be little respite.'

Tamworth reached 37 degrees Celsius on Thursday afternoon, ahead of the busiest two days of the Country Music Festival, which attracts tens of thousands of visitors to the region.

One of the festival's main live venues, The Longyard Hotel, was packed with revelers cooling off with a drink or two on the veranda.

Wide-brimmed cowboy hats were put to good use in the scorching sun.

At the City Lights holiday park on the edge of the city, campers could cool off with a shower or in the shade of tarpaulin and eucalyptus trees.

Jo O'Donoghue and her husband traveled to the festival from Corowa on the NSW-Victorian border.

The couple escaped the heat in their air-conditioned caravan.

“I would have liked to go out and see more but it's so bloody hot,” Ms O'Donoghue told AAP.

“I don't know how the artists do it.”