Keep your pet cool. Make sure your animal has plenty of fresh water and a shady spot to sit when it is outside (but if it’s above 90 degrees or so, your pet will appreciate staying home in the air-conditioning). Don’t exercise your dog outdoors during the hottest part of the day, from 10 a.m. to 2 p.m. Walk your pup early in the morning or at night.
Recognize the signs of heatstroke. Your dog is likely overheated if it staggers or becomes lethargic, or if its gums are red or dark pink and feel warm or dry to the touch. If this happens, take your pet to a vet immediately―heatstroke can cause permanent damage to the brain, organs and blood vessels and is often fatal if not treated right away. Flat-faced dogs, like bulldogs and pugs, and older and overweight pups are at higher risk for heatstroke, so take extra care when they’re in the sun (cats aren’t as susceptible to this condition).
Don’t leave your pet in the car. Just running into the bank or grocery store for a few minutes can be disastrous. Even on a 70-degree day and with the windows cracked, the temperature inside your vehicle can rise and cause heatstroke in a matter of minutes.
Protect animals around water. Don’t leave your dog alone around a swimming pool―it could jump in and become exhausted or not be able to get out unassisted. Also, be sure dogs wear pet life jackets while on boats (available at petco.com or petsmart.com).
Take longhaired pets to the groomer. A trim can help keep your cat or dog cool, but don’t get it completely clipped or shaved. Your pet's coat protects it from sunburn and acts as an insulator, helping it stay cool and regulate its body temperature.
Source: Dr. Louise Murray, director of medicine for the American Society for the Prevention of Cruelty to Animals’ Bergh Memorial Animal Hospital in New York City