Officers urged people not to forget about their pets during the heatwave.
Police in Wednesfield had to rescue the dog from baking car.
Wolverhampton Police shared an image of the dog on Facebook saying: "Unbelievable! On a sunny day like this (28C) someone left this dog trapped in a car with only an inch gap in the window.
"Luckily, a member of the public alerted us and our Wednesfield PCSOs responded immediately and got in to rescue the suffering dog.
"Let's not forget about our four-legged friends during the heatwave."