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Dog Health & Care

How Hot Is Too Hot to Leave Your Dog in a Car? Legalities & Temperature (Vet Verified)

Rachel Giordano
By Rachel Giordano · Reviewed & fact-checked by Dr. Lauren DemosVet Approved
Dr. Lauren Demos
Reviewed & Fact-Checked byDr. Lauren DemosDVM (Veterinarian)
As a veterinarian, Lauren is happy to share her rich experience in emergency medicine and cats, with our readers. She enjoys sharing helpful, real life tips for having pets as part of your life, and what to do in critical situations.View authorThe information is current and up-to-date in accordance with the latest veterinarian research. Learn more
Updated on June 17, 2026
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dog in a car wearing harness

Many dogs love to ride with their owners to run errands or around town. A dog owner may not think twice about leaving their dog in the car while they run inside to grab a few items in the store, even if the outside temperature is only 60 degrees Fahrenheit. Surely, a dog will be fine inside a car for a few minutes, right? Wrong.

If the outside temperature is 70 degrees, the inside of a vehicle with no air conditioning can reach 89 degrees in just 10 minutes and 99 degrees in 20 minutes. In short, no dog should ever be left inside a parked car, no matter the outside temperature.

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How Hot Is Too Hot for Dogs in Cars?

It doesn’t take long for the inside of a car to reach dangerous temperatures. According to the American Veterinary Medical Association (AVMA), the temperature inside a parked vehicle can rise 20 degrees Fahrenheit in just 10 minutes and almost 30 degrees in 20 minutes. Ironically, that is the typical amount of time it takes to run inside a grocery store to pick up a few items. If you think your dog will be safe in this short amount of time with no air conditioning, think again.

A dog can suffer heatstroke and/or organ damage and in a parked car in just minutes, especially if the outside temperature is 90+ degrees. On a 90-degree day, the inside of a parked vehicle can reach 109 degrees in 10 minutes and 119 degrees in 20 minutes.

That said, no dog should ever be left in a parked vehicle, regardless of the outside temperature. Dogs are susceptible to overheating (hyperthermia) because they only regulate heat through sweat glands on their footpads and through panting—they simply cannot cool themselves down like humans. As you can see, a car doesn’t take long to become an oven for a dog trapped inside.

Image Credit: Andrey Popov, Shutterstock
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Is It OK to Leave a Dog in a Car With the Windows Cracked?

Despite popular belief, leaving the windows cracked for a dog in a car makes little difference. The inside temperature of a parked vehicle will still reach dangerous levels in a few short minutes. It’s best to leave your dog at home if you have errands to run.

Can I Leave the Engine Running With the AC On?

It's not recommended to leave the engine running with the AC on because the AC could malfunction or your car could run out of gas. This is not an ideal scenario. It's also important to note that cars usually do not cool off as well inside while they are idling.

You may also run the risk of someone busting your window out if they are not aware the engine is running. Some cars today run quietly, and a person may not hear that the engine is on.

Image Credit: Gorloff-KV, Shutterstock
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Currently, some US states declare it legal to bust out a window to save a trapped dog in a hot car however there are conditions to this law, and in some states, only emergency personnel are cleared to do so. Each state has its own laws regarding this issue, which vary from state to state.

There are 15 states with “Good Samaritan” laws regarding dogs trapped in cars—this means a person can act to save a dog in a car if they are in immediate danger. We recommend reading the provisions of this law in your state in order to avoid criminal charges and liability.

Thankfully, even if a state does not have laws in place for saving a dog trapped inside a car unattended, every US state has some sort of law against animal cruelty and abuse. If you are concerned about a dog’s welfare, you should call the local authorities.

It’s wise to know the laws in your particular state so that you know what legal action you can take if you encounter this type of scenario.

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Are Particular Breeds More Susceptible to Heatstroke?

Absolutely. Brachycephalic (flat-faced breeds) are more at risk for heatstroke due to their short noses and smaller airways, like the Boston Terrier, Bulldog, Boxer, and Pug, to name a few. These breeds overheat quickly and should never be subjected to hot weather for any extended period of time. Overweight dogs are also more susceptible, along with dogs with certain pre-existing medical conditions.

Image Credit: Kellis, Shutterstock

Signs of Overheating in Dogs

If you happen to stumble upon a dog trapped inside a hot car, it’s vital to know the signs of overheating and distress so that you can act accordingly.

Signs of overheating in dogs are:

  • Frantic panting
  • Extreme salivation
  • Labored breathing
  • Wide, stressed eyes
  • The tongue, gums, and inside of ears are bright red
  • Pale gums
  • Gasping for air
  • The entire mouth is grayish or purple
  • Vomiting
  • Diarrhea
  • Unable to stand
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Conclusion

No matter the outside temperature, no dog should be left inside a car, period. It is never safe to leave your dog in a car, even with cracked windows or the engine running with the air conditioning on, as the AC does not cool as well while a vehicle is idling. If you need to run errands, leave your best friend at home unless you never plan to leave the car with your dog inside.

Sources

Featured Image Credit: Aleksey Boyko, Shutterstock

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Rachel Giordano
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