The hottest September day for a Queensland town has been recorded at Birdsville, but while locals are sweltering, the national record maximum temperate for spring is set to remain unbroken.

The mercury rose to 42.5 degrees on Wednesday afternoon, surpassing the previous state record by 0.1 if a degree and it was expected to stay there before a cool change brings relief to the area on Wednesday afternoon, a Bureau of Meteorology spokesman said.

The famous Birdsville Hotel would have been a popular place as temperatures soared. Credit:Darren England/AAP

There was a small chance temperatures would surpass the national record of 43.1 degrees, which was set in Roebuck, outside Broome in Western Australia, in 2003.

But that was not likely, the BOM spokesman said.