The owner has since been arrested for drink driving, it is reported. Police had previously been alerted to a parked car after noticing the dog struggling inside in Southend, Essex, on Saturday.
The pooch, which appears to be a terrier breed, was left “gasping for air” as temperatures in the district soared over 20C.
Officers had to smash the car windows to free the dog, who is now healthy, Essex Live reports.
Southend Community Safety Partnership and officers from Southend Borough Council helped police.
Safer Southend said on Twitter: “Good work with Essex Police Southend, Southend BID and Southend Borough Council.
“A dog was locked in a car for over 3 hours in this heat, owners were in a pub, window smashed as the dog was gasping for breath – now safe. Later, the owner drove away and shortly after was arrested for drink driving”.
A car can become as hot as an oven very quickly, even when it doesn’t feel that warm. When it’s 22C, in a car it can reach an unbearable 47C within the hour.
These temperatures are incredibly dangerous for animals to be locked away inside.
According to the RPSCA, if you see a dog in a car on a warm day, dial 999. The police will inform the RSPCA if animal welfare assistance is required.
In an emergency, RSPCA may not be able to attend quickly enough, and with no powers of entry, police assistance is required at such an incident, they say.