The gauge peaked at 40.8C at 2.21pm in the outback town. That beat a record set just four days previously when Wilcannia, in the west of NSW, hit 40.5C.

Over the last week parts of NSW and Queensland have been experiencing temperatures far higher than the average, more akin to a mid summer heatwave than the start of spring.

While Tuesday’s highs were contained to the inland, the searing heat is due to hit more populated areas tomorrow with forecasts for parts of Brisbane to hit 39C.

Just a few days ago, parts of NSW recorded their hottest ever September day.

But the mercury screeched past that today on both sides of the border. The Delta weather station, in western NSW, reached 41.3C.

Birdsville, the famed outback Queensland town, reached 42.7C at 3pm, just shy of the hottest ever Spring day in Australia. The record set at Roebuck, outside Broome in Western Australia, in 2003, when the mercury rose to 43.1C stands.

But, climate wise, it’s a tale of two countries. While the north swelters, the south and west has been distinctly average weather wise.

Perth struggled to reach 17C on Tuesday and both it and Melbourne are likely to see showers.

The Bureau of Meteorology says outback Queensland is being hit by a blast of hot air drawn down from the country’s north.

“There’s a lot of warm air in the upper atmosphere. Not only is it windy, it’s also sinking and as it sinks it warms even more,” meteorologist Adam Blazak told AAP.

Other towns in Queensland’s Channel Country were not far behind Birdsville, with Bedourie, Boulia, Quilpie, Thargomindah and Windorah near 42C as another spring wave of heat sweeped parts of the state.

There is some respite ahead for Birdsville and surrounding communities as the warm air is replaced by much cooler air from the south.

On Thursday, Birdsville is expected to be 12 degrees cooler at 31C, But by then it will be the turn of Queensland’s southeast to see temperatures spike.

As the warm air mass moves towards the coast, bringing hot and windy conditions, Brisbane’s CBD could see a high of 36C, the Sunshine Coast 35C, Ipswich a whopping 39C with the Gold Coast a little cooler at 32C.

Fire bans are in place for the Sunshine Coast, Noosa, Gympie and South Burnett council areas and will remain in force up to and including Saturday.

Fire bans will be extended on Thursday to cover the Moreton Bay, Brisbane, Redland, Ipswich, Somerset, Lockyer Valley, Logan, Scenic Rim and Gold Coast council areas.

WHERE WILL IT BE HOT AND WHERE WILL IT NOT?

On Wednesday, much of the really hot weather has been confined to inland areas of NSW and Queensland.

On Thursday, that warm front will hurtle towards the Queensland coast bringing temperatures in the mid to high thirties.

South of the border, things are much more manageable but still balmy.

Sydney will see a unseasonably warm high of 27C on Thursday. But the gauge plummets as you go south. Canberra will get to 21C with rain. Melbourne will reach 18C and Hobart 15C, both with possible showers.

Adelaide and Perth will both get to 18C but in wet Western Australia watch out for possible thunderstorms.

Darwin will be 34C, dry and sunny (albeit a little humid, it is the start of the build up, after all).

— with wires