When temperatures outside reach dangerous levels, the temperature inside the house can, too. Keep fresh water available, and make sure your cat has a cool place to spend the day.
Bring your cat indoors if a heat advisory is issued, or if severe weather (heavy rain, high winds, flooding) is expected.
Keep vaccines up to date, have your cat spayed or neutered, and continue parasite control throughout the summer.
Regardless of whether your cat spends time outdoors, exposure to dangerously high temperatures, environmental hazards, and physical dangers is possible. Knowing what to look for is the first step toward protecting your cat from potential summer hazards.

What Should I Know About Warmer Temperatures and Heatstroke?

Cats that don’t go outside are protected from many warm weather hazards, but only if the temperature inside the home remains within a healthy range. In an effort to reduce energy usage and costs, some pet owners shut off fans and air conditioning when they leave the house in the morning and turn them on when they return later in the day. However, when temperatures outside reach dangerous levels, temperatures inside the house can, too. Being shut inside a hot house can be dangerous for your cat. Like dogs, cats can rely on panting to cool themselves off. When the temperature in the environment increases, panting becomes less effective. This means that your cat could be locked inside with minimal options for cooling down.

Instead of turning off the air conditioner, try leaving it on a conservative but comfortable setting (perhaps 76°F) while you are out. Make sure your cat has plenty of fresh water, and consider closing curtains to reduce the heating effects of sunlight through the windows. If there are parts of the house that are likely to be cooler, make sure your cat has access to those areas.

Cats that go outside need even more protection from hot weather. Access to clean drinking water is essential, as well as making sure cool, shaded areas are available if your cat wants to get out of the sun. Remember, however, that fleas also tend to like cool, shaded, moist areas, so be sure to use a safe and effective flea control product on your cat. Cats should not be left outside for long periods of time in the summer and should always have the option of coming inside. It’s important to be aware of the risk of heatstroke so you can keep your cat safe and healthy.

Cats tend not to develop heatstroke as commonly as dogs do, perhaps because cats tend not to exercise with humans and spend less time in the car. However, even a few minutes in a car (even with the windows cracked) on a hot day can be deadly for a cat. Research has shown that on a partly cloudy, 93°F day, a car can heat up to 120°F in just 15 minutes. Even cooler days can be deadly. A similar test conducted on a 71°F day determined that the temperature inside a car parked in the sun with the windows cracked open went up to 116°F in 1 hour.

Even cats that are used to being outside can suffer during hot weather. Remember that young, elderly, or sick cats are more likely to become dehydrated or otherwise ill as a result of heat exposure. If a severe heat advisory is issued in your area and humans are advised to stay indoors, it is a good idea to bring your cat indoors, too. If your cat cannot be brought indoors, a ventilated or air-conditioned garage or mud room can provide enough shelter in some cases. Cats should also be brought inside if severe weather is expected, as heavy rain, flooding, and high winds can be hazardous, especially for cats that are hiding under cars or in other low-lying areas.

Why Are Strange Animals and Other Cats Hazardous?

Cats that are allowed to roam outside are more likely to have encounters with other cats and wild animals during the summer months. Such encounters increase the risk of bite wounds, scratches, and other injuries related to fighting. Infectious diseases such as rabies and feline AIDS can be transmitted through bite wounds. Additionally, female cats’ fertility cycles are linked to the length of time they are exposed to daylight. Female cats tend to start going into heat in the spring, and they may go into and out of heat repeatedly for several months. Unwanted pregnancies and litters of kittens increase dramatically in the summer, which contributes to pet overpopulation, the spread of infectious diseases, and other issues.

Protect your cat from these hazards by having him or her spayed or neutered and keeping vaccines up-to-date. Keeping cats indoors not only protects them from a variety of animal encounters, it also prevents them from being injured or killed by cars.

What Toxic Chemicals Might My Pet Be Exposed To?

Lawn chemicals and fertilizers, insect repellants and sprays, weed control products, antifreeze, slug bait, ant bait, rat poison, and pool chemicals are just a few toxic chemicals your cat may encounter in your home or on your property. Learn more about dangerous chemicals at the ASPCA (American Society for the Prevention of Cruelty to Animals) Animal Poison Control Center: http://www.aspca.org/pet-care/poison-control/.

How Can I Prevent Bee Stings and Related Hazards?

Bee stings, spider bites, and other related injuries are common in cats. Keeping your cat indoors reduces the risk of these things, but it is a good idea to check around your home (inside and out) for beehives, wasp nests, and other hazards your family and pets may encounter. Don’t forget to also check garages and storage sheds.

How Can I Prevent Fleas, Ticks, and Other Parasites?

Fleas, ticks, and intestinal parasites (like roundworms and hookworms) are year-round hazards for your cat. However, increased exposure to the outdoors and certain parasite life stages during the warmer months makes these predators more of a concern during the summer. Be sure to keep your cat up-to-date on fecal parasite testing, and make sure you continue flea, tick, and parasite prevention during the summer months. If your cat receives heartworm preventive medication, continue this during the summer (heartworm disease is carried by mosquitoes, which are mostly active from the spring through the fall). If you are using a flea and tick control product for your cat, be sure you purchase the correct product and that you are using it properly. Never use a dog product on a cat. Ask your veterinarian about the best ways to protect your cat from fleas, ticks, heartworms, and intestinal parasites.

What Should I Know About Toxic Plants?

Your cat may encounter toxic houseplants (such as elephant ear and dieffenbachia) at any time of the year, but plants that flower in warm weather, like daisies, dahlias, lilies, and chrysanthemums, are also toxic and create additional hazards for cats that go outside. Information about poisonous houseplants and outdoor plants and flowers is available at the ASPCA Animal Poison Control Center: http://www.aspca.org/pet-care/poison-control/.