The mercury soared highest in the outback town of Windorah which reached 45.5C for the second successive day, the hottest February temperature since recordings began in 1887.

The sweltering heat, which the Bureau of Meteorology was tipping would deliver a statewide record of average hot temperatures, also saw 45C at Winton and a February record of 44.5 at Barcaldine.

There were also record hot minimum temperatures around the state, highlighted by Isisford only dropping to 33.9.

Winton broke its February record for the highest minimum temperature at 31.3C.

Even Brisbane only got down to 26.3 overnight as residents woke up to sauna-like conditions with 85 per cent humidity.

The BOM is forecasting more hot and humid conditions on Wednesday, while Julia Creek is tipped to eclipse 46C on Thursday before temperatures ease on Friday.

Bureau of Meteorology forecaster Annabelle Sord told AAP the "unstable" system could lead to more storm activity after Sunday night's weather event damaged power lines and left thousands without power.

"There's really high humidity, which has made it feel even hotter," Ms Sord said.

The humid and hot temperatures are expected to continue until the weekend.

"By Friday it should get a few degrees cooler and the humidity should drop," Ms Sord said.

Australian Associated Press