How Hot Is Too Hot for Cats Indoors?

When outdoor temperatures drop below 45℉ (7℃), a cat can count on her thick fur and layers of body fat to keep her warm while also avoiding cold-weather conditions like hypothermia or frostbite. But a cat’s body can handle colder weather far better than it fares in the summer heat and humidity. Overheating in cats can be fatal — so how hot is too hot for cats indoors?

Temperatures over 90℉ (32℃) are too hot for cats. Heat exposure can raise a cat’s body temperature above 102.5℉ (39℃) and cause heatstroke, and cats with long hair and short snouts struggle even more in the heat. Access to shade, cold water, and airflow can reduce the effects of high heat in cats.

The good news is that setting your indoor thermostat to a cozy 75℉ (24℃) in the winter won’t suddenly trigger the onset of heatstroke in your cat. To learn more about cats and their tumultuous relationship with heat, read on!

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A Cat’s Ideal Temperature Range

The average cat has an internal body temperature between 101°F-102.5℉ (38°C-39℃), only slightly higher than ordinary humans. While you can turn up the air conditioning in the summer or pile on extra layers of clothing in the winter, all your cat has is her coat and body fat.

An outdoor temperature between 45°F-90℉ (7°C-32℃) is generally safe for cats and comes with a lower risk of leaving the ideal body temperature range. However, the elements are just as essential, and the following can make your cat feel hotter or colder than usual:

Direct sunlight can make it feel 10-15 degrees warmer than the outdoor temperature.
50%+ humidity can raise the “feels like” temperature by 10-40 degrees.
A satisfying breeze can make it feel more than 5 degrees cooler than it is.
Rainy weather can cause an unexpected bout of hypothermia.

In other words, 45-90℉ (7°C-32℃) is ideal for cats in near-perfect conditions. If it’s humid without a breeze in the middle of the day, the mid-70s might be more comfortable for your cat.

Is 80 Too Hot for a Cat?

An 80℉ (27℃) temperature isn’t too hot for cats and rarely comes with a risk of heatstroke in controlled conditions (i.e., no absurdly high humidity or shelter from sunlight). However, some cats — particularly seniors or obese cats — may find 80℉ (27℃) to be uncomfortably warm.

Now, you might be wondering, “If my cat willingly sunbathes for hours on end in the summer, how is 80℉ (27℃) too warm?” Cats can (and do) overheat while sunbathing, but most cats know when to end the tanning session and take the time to cool down.

For example, you might notice that your cat drinks from her water bowl, lies down on the cold tile floor, or sits in front of the air vent after lounging in the sun for a while. Felines who venture outside usually may also take shelter in a garage when it’s 80℉ for too long.

So, while you might like the thermostat set to a cozy 80℉ (27℃), about 70℉ (21°C) — give or take a few degrees — is more comfortable for your cat.

Why Some Cats Tolerate Heat Worse Than Others

Some cats don’t seem bothered by steady 100℉ (37.8°C) temperatures, while other cats may suffer from breathing problems well before that point. Here are a few reasons particular cats struggle to tolerate the heat more than others:

Age: Kittens cannot fully control their body temperatures until about the one-month mark, and they rely on their mother cat for temperature regulation until then. Also, seniors might struggle with high heat more than adolescent cats may.
Hair length: The more body hair a cat has, the more heat becomes trapped under their thick fur, making them feel hotter than a shorthair cat might. Alternatively, breeds like the Sphynx are more susceptible to sunburn since their skin is exposed to direct sun.
Obesity: An obese cat will typically have a thicker layer of body fat, meaning the high temperatures hit them quicker and more severely. When an overweight cat becomes overheated, it’s hard for them to cool back down.
Short snouts: Cats with brachycephaly (pushed-in noses), like Exotics and Persians, have trouble breathing in high heat and humidity, leading to severe panting. A short snout is the same reason many groomers won’t put a Pug in a drying kennel.

Before you let your cat roam around outdoors or hang out in a hot apartment, make sure she doesn’t meet any of the criteria above. Otherwise, every extra degree might make it harder for her to breathe or put her one step closer to developing heatstroke.

How Do I Know if My Cat Is Too Hot?

Fortunately, cats show visible signs when their body temperature increases above normal and reaches a point of discomfort or distress. The following signs demonstrate that your cat may be too hot and require immediate cooling:

Panting (the first clear indicator that something is wrong)
Restless behavior
Drooling
Non-stop grooming

Giving your cat a bowl of cold water and bringing her into a cooler room in the house (like the garage or basement) could help to cool her down. If left untreated, these symptoms will only worsen as your cat nears the point of heatstroke — a dangerously high internal body temperature of at least 105°F (41℃).

By this stage, your cat may begin vomiting, present with dark red gums, or struggle to walk. A quick vet visit is necessary if you want to avoid permanent organ damage or death.

The video below discusses heatstroke in cats even more in-depth:

How to Keep a Cat Cool & Comfortable

The good news is that cats thermoregulate rather well. Cats will sweat through their paws to cool down to trigger a cold sensation when the air hits it. A cat might also vigorously lick her fur to create this same evaporation effect.

Yet, as a cat owner, you play a larger role in your cat’s ability to keep cool than she does. To help your cat feel cool and comfortable, here’s what you can do:

Give unlimited access to fresh, cold water. Not only will this cool your cat down from the inside out, but it’ll also fend off dehydration — an unfortunate side effect of the heat.
Provide somewhere cold to relax. A cooling mat, dark room, tile floor, fan, or covered cardboard box can all lower your cat’s body temperature and keep her out of the sun.
Make things intentionally cold. Feed your kitty frozen treats or put a frozen water bottle wrapped in a shirt by her bed (for hypothermia, you’d use warm water).
Check the temperature early. It might be 60℉ (16℃) first thing in the morning but become dangerously hot by midday — judge the temperature by the day’s highs.

You may be unhappy about the cold indoor temperature, or your cat may be miserable spending the entire day inside. Both of these things are better than a case of hyperthermia (heat stroke) that could be life-threatening for your beloved feline.

Conclusion

Thankfully, your cat should be okay if the A/C goes out temporarily or if she spends a few hours in the heat. As a general rule of thumb, if it feels too hot for you to be outside, it’s too hot for a cat with a thick coat.

Therefore, try to keep your cat indoors when temperatures soar above 90℉ (32℃). If you can’t bring your cat inside, provide her with a shelter out of direct sunlight and a bowl of chilled water, and if your cat begins showing signs of heatstroke, take her to the vet immediately.

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Pam Turner

Pam is a self-confessed cat lover and has experience of working with cats and owning cats for as long as she can remember. This website is where she gets to share her knowledge and interact with other cat lovers.