Taking the Heat: How Hot Is Too Hot for Dogs?

Ahh, summer: the season of sunshine, smiles and sweltering heat. It’s a welcome reprieve from the cold, dark dregs of winter, but with the warmer weather comes a new risk for your dog.

Extreme heat can be just as dangerous as extreme cold, especially for dogs, who are covered in fur and lack the wide array of sweat glands that keep us humans cool. Dehydration, exhaustion, heat stroke and even death can result from spending too much time in the heat.

But just how hot is too hot for your dog? And what can you do to keep him cool when the sun’s blazing?

We’ve got your answers right here.

Heat Factors for Dogs

Dog near the tree is heat

The maximum temperature your dog can withstand depends on many factors: his size, breed, weight, coat, age and hydration levels, plus the amount of shade and the relative humidity.

Small dogs can handle more heat than large dogs, and the same goes for weight; obese dogs are much more likely to overheat than dogs at a healthy weight. Dogs with dense or double coats are more susceptible to heat sickness than dogs with thin coats.

Brachycephalic, or short-snouted, breeds have a harder time breathing and regulating their body temperatures than other breeds. Pugs, French bulldogs, Chow Chows and similar breeds overheat far more readily than others.

Very young (under 6 months), very old (more than 12 years) and sick dogs can’t handle the high temperatures that healthy adult dogs can. These high-risk groups are more likely to suffer complications from the heat.

Humidity impacts the way the weather actually feels and can greatly impact the tolerability of heat. An 80 degree day at 50% humidity may feel pleasant enough, but crank the humidity up to 90% and it can become unbearably warm and difficult to breathe.

Finally, areas with partial or full shade will be much cooler than areas in direct sun. If you’re taking your dog for a walk through a tree-lined park, he’ll be able to withstand higher temperatures than he would if you were walking through a sunny meadow.

Maximum Temperatures for Dogs

All of the above factors need to be considered when deciding whether it’s too hot for your dog. But there are a few rules of thumb you can use as starting points for your decision.

In general, small and medium brachycephalic dogs are fine up to 75 degrees Fahrenheit, and non-brachycephalic breeds can readily handle up to 80 degrees. At 85 degrees, you’ll want to keep a close eye on your dog for signs of overheating, and at 90 degrees or more, outdoor activity should be limited to what’s necessary.

Large dogs should be fine when it’s under 70 degrees, but after that, things start getting risky. At 75 degrees, brachycephalic breeds can begin having breathing issues, and at 80 degrees or more, all large dogs need extra care to stay cool.

When temperatures rise above 102 degrees (a dog’s normal body temperature), they lose the ability to cool their bodies down. Dogs should not be exposed to these temperatures for longer than a minute or two, regardless of size.

If your dog is obese, sick or heavy-coated, the safe temperature range compresses considerably. Limit outdoor time when it’s hotter than 80 degrees.

When reading temperatures, be sure to take humidity into account. Look for the “feels like” temperature on the weather forecast to get an idea of the effective temperature including humidity.

It’s also a good idea to place a thermometer in both the sun and the shade if you plan to let your dog outside. Even if air temps are high, they may be acceptable in the shade, so you might be able to let your dog relax under a tree or on your porch instead of out in the full sun.

Playing it Cool

Sad french bulldog on the sun

If the sun’s blazing, you’ll need to pay extra attention to your dog to make sure he’s not overheating. Overheating can cause serious complications, so it’s important to know the signs.

Heavy panting when at rest, especially when accompanied by drool, is a strong indicator that your dog is too hot. Other symptoms include weakness, confusion and muscle tremors.

Dehydration is another serious issue that’s common when temperatures rise. Symptoms include dry nose and eyes, tacky gums, vomiting and weakness.

As soon as you notice these symptoms, bring your dog to a cool area and provide him with water to drink. Go to the vet immediately if he doesn’t improve within 15 minutes.

Heat Stroke in Dogs

If your dog overheats for extended periods of time or is left in extreme heat, he could go into heat stroke, which is fatal if untreated. Heat stroke begins when your dog’s body temperature rises above 105 degrees and is characterized by rapid heartbeat, seizures, glassy eyes, heavy panting, and collapse.

Get your dog to the vet immediately if you suspect heat stroke. 50% of dogs that are diagnosed with heat stroke do not survive, so early treatment is vital.

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