Why Is It Dangerous To Leave a Dog in a Hot Car?

Learn the dangers of leaving a dog alone in a parked car—even for a few minutes.

No Single Riders

We’ve seen them in the parking lots of strip malls and supermarkets. Dogs left in parked cars, maybe sitting in the driver’s seat quietly looking out the windshield or pacing in the backseat, barking at passersby. We may even have been tempted to run into the store quickly ourselves while our canine friend was in the car.

But it’s never a good idea to leave a dog alone in a parked car. Never. And dog experts from breeders and dog trainers to vets to behaviorists strongly advise dog owners to either leave their pets at home while running errands, or only visit those stores where the dog is welcome inside. Now that summer has arrived, here is what you should know about the dangers of leaving a dog inside a parked car.

How Hot Can Your Car Get?

If you stop to think about it, you may realize that a car is a heat trap waiting to happen. Made of metal and often painted in dark colors, cars attract heat instead of repelling it. Plastic, rubber, vinyl, and glass components also trap, conduct, and distribute heat efficiently and effectively. You know that feeling when you sit on a hot vinyl or leather seat when you get back into your car? Or put your hands on the plastic steering wheel? Parking in the shade only does so much to reduce these effects.

Multiple studies have revealed that the temperature inside a parked car rises rapidly—more rapidly than you might expect. One study conducted in 2002 found that the temperature inside an enclosed car rose 19 degrees F in just 10 minutes. The study further found that 80 percent of the overall temperature rise inside the car occurred in the first 30 minutes, and that cracking windows was not effective at reducing or delaying the temperature rise.

Canine Anatomy and Rising Temperatures

A dog’s physical makeup only exacerbates the effects of the rising heat inside a parked car. While dogs can sweat, their sweat glands are located only in their noses and paw pads—not much surface area to deal with hot temperatures. A dog primarily deals with heat through panting, but panting alone cannot keep up with the rapid rise of temperature in a hot car. When a dog pants, he releases moisture, and the more he pants to keep up with a car that continues to get hotter, the greater his risk of dehydration.

Additionally, a dog’s average normal body temperature—taking into account the wide variety of sizes and types of dogs—ranges from 99.5 to 102.5 degrees F. When his temperature reaches 106 degrees F, a dog can begin to show signs of heat stroke, including drooling, reddened gums, vomiting, diarrhea, loss of consciousness, uncoordinated movements, and collapse. Heat stroke can cause unseen problems, too, such as kidney failure, intestinal bleeding, and swelling of the brain. And the longer a dog is exposed to extreme heat, the more intense the damage to his body.

According to the American Kennel Club, a dog can begin to feel the adverse effects of the heat when the temperature is just 81 to 85 degrees F. And as we’ve already learned, the temperature in a car can rapidly climb much higher than that in just 10 minutes.

Some dogs are more sensitive to heat and may show signs of heat stroke sooner than others. Young puppies and senior dogs are more fragile health-wise to begin with, and dogs with thick fur, short noses, or pre-existing medical conditions also are predisposed to heat stroke. (If you suspect your dog has heat stroke, follow the steps in the sidebar “Cooling Off” and take him to the vet immediately.)

Taking Action Against Pet Hyperthermia

You may be saying to yourself, “Of course I would never leave my dog in a hot parked car.” But what should you do if you see this situation in the parking lot of the supermarket?

Most animal care specialists suggest that you first try to locate the owner of the car in question. Write down the car’s make and model, as well as its color and license plate number. Step into the store nearest to the car, and ask the manager to page the owner. If you locate the owner, express your concern politely, perhaps even offering to stay with the dog outside while the owner finishes up their errand. Remember that not everyone understands the dangers of leaving a dog in a parked car. While you might be understandably upset, confronting someone angrily could lead to their unwillingness to cooperate. Your primary concern should be the safety of the dog.

If, despite your best efforts, you can’t locate the owner, call the local animal shelter or the non-emergency number of the local police department to report the situation. Stay near the car to keep an eye on the dog until help arrives.

What do you do if the dog is showing signs of extreme distress? Your actions to help a dog in this situation may be protected by “good Samaritan” laws, depending on which state you live in. As of May 2019, these 28 states have laws prohibiting leaving an animal confined in a vehicle under dangerous conditions: Arizona, California, Colorado, Delaware, Florida, Illinois, Indiana, Kansas, Maine, Maryland, Massachusetts, Minnesota, Nevada, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Oregon, Rhode Island, South Dakota, Tennessee, Vermont, Virginia, Washington, West Virginia, and Wisconsin. The exact language of these laws can be found at www.animallaw.info.

Cooling Off Your Canine

Your canine companion can start to show signs of heat stroke when the temperature is just 81 to 85 degrees F. Even if he isn’t left in a hot car, your dog can be susceptible to the effects of higher temperatures during warmer summer months. Luckily, you can take steps to make sure your dog stays cool and safe.

Make sure your dog has a shady spot to rest if he must be left outside during the day. Keep him inside the cooler temperatures of your home during the hottest parts of the day.
Always provide clean, cool water for your dog. To help your dog maintain his regular temperature, consider adding ice cubes to his water bowl.
Avoid playtime in the hottest parts of the day. Save long walks and games of fetch for early morning or late evening.

Despite your best efforts, your dog may still succumb to hot summer temperatures. If you suspect your pet has heatstroke, immediately remove him from the hot environment, call your veterinary team, then follow these steps:

Cool him off with cool water. Put him in the bathtub, hose him down (make sure the water in the hose isn’t hot), or place a soaking wet towel on his back and apply cool water to the paws. If he is disoriented or unconscious, take special care not to get water in his nose or mouth.
Let your dog drink as much cool water as he wants—but don’t force him to.
Do not administer any medications as you would for a human experiencing a fever.
Get him to the vet as soon as possible for further treatment.
Never use cold water when trying to cool your pet off. This could pose a shock to their system.