The Bureau of Meteorology said temperatures in many towns and cities, which included Brisbane and Ipswich, could soar into the high 30s, and the mercury could reach above 40 degrees in areas like Longreach, Mount Isa, Roma and Winton.
RACQ spokesperson Clare Hunter said it was a timely reminder to never leave children and pets in cars.
“There’s never a safe amount of time to leave a child or pet locked in a car,” Ms Hunter said.
“Even with the windows down, a car can reach dangerously high temperatures in minutes.
“Make sure you don’t give your car keys to the child to play with or hold, because this is the most common way babies are accidentally locked in.”
Ms Hunter reminded pet owners it was also dangerous to leave an animal on the back of a ute as the tray could get very hot and burn a dog’s paws.
“If you see a child or pet trapped in car call RACQ on 13 11 11 or emergency services.”