Pets respond to heat differently than humans do (dogs, for instance, sweat primarily through their feet), and fans don't cool off pets as effectively as they do people. Animals pant to evaporate moisture from their lungs, which takes heat away from their body, but if the humidity is too high, they are unable to cool themselves and their temperature will skyrocket to dangerous levels very quickly.
Provide ample shade and water. Any time your pet is outside, make sure he or she has protection from heat and sun and plenty of fresh, cold water, add ice when possible. Tree shade and tarps are ideal because they don't obstruct air flow. A doghouse does not provide relief from heat.
Take care when exercising your pet, and limit exercise on hot days. Adjust intensity and duration of exercise in accordance with the temperature. On very hot days, limit exercise to early morning or evening hours, and be especially careful with short-nosed pets who, because of their short noses, typically have difficulty breathing. Asphalt gets very hot and can burn your pet's paws, so walk your dog on the grass if possible.
Provide cool treats. There are hundreds of recipes online for frozen peanut butter, yogurt and fruit treats for your pet. Switch out your pet's regular bisquits or dry treats to something cool and refreshing during hot months.
Never leave your pet(s) in a parked car! Not even for a minute.
On a warm day, temperatures inside a vehicle can rise rapidly to dangerous levels. On an 85 degree day, for example, the temperature inside a car with the windows opened slightly can reach 102 degrees within 10 minutes. After 30 minutes, the temperature will reach 120 degrees. Your pet may suffer irreversible organ damage or die.