The cockapoo named Bertie was reportedly left in the sweltering car with no windows in a car park in Saffron Walden, Essex on Friday – where the temperature soared to 24C.
Firefighters were unable to find Bertie’s owner and smashed their way into the car at around midday.
The fire service said the dog had been left alone in the car with no ventilation for more than an hour and appeared “distressed”.
Bertie was spotted by a member of the public who called the fire service.
It is claimed the dog’s owner had been shopping at a local Waitrose but didn’t respond to announcements on the store’s tannoy.
Essex Fire and Rescue wrote on Facebook: “Today we rescued a Cokerpoo Dog called Bertie from the top deck of Waitrose multi story park car in SW by breaking a window to release him.
“The dog was in distress due to the intense heat within a parked car in direct sunlight with no open windows.
“Please always keep your pet’s welfare and safety in mind particularly during this hot spell.
“Thankfully Bertie survived to tell the tale! We thank Waitrose staff for their support with trying to help locate the owner and for providing much needed water for Bertie.”
Essex police said: “We were called at around 12.15pm yesterday, Friday 28 June, with concerns about a dog in a vehicle parked at Waitrose, in Hill Street, Saffron Walden.
“Entry was forced to get access to the animal before the dog’s owner was located.
“He received words of advice before becoming unwell and receiving care at the scene.”
While is isn’t illegal to leave a pet unattended in a vehicle if the animal gets ill or dies its owner could be charged with animal cruelty.
If convicted pet owners could be jailed for six months and slapped with an unlimited fine.