In fact, cats combine several of these techniques to cool down in hot weather:
"Sweating" from their coats: Cats lick their coats to cool down which is why your cat may groom himself more in the summer. When saliva evaporates from your cat's fur, it provides a cooling effect, similar to a human's sweat evaporating off of their skin.
Panting: When your cat gets very hot, he may begin to pant. The rapid breathing, similar to a dog's panting, allows saliva to evaporate from their tongue and allows them to cool down.
How to help: If you notice your cat breathing rapidly or struggling to find comfort, you may need to intervene. Seek out a cool, dark place inside for your cat to relax and provide plenty of water. Consider setting up air conditioning or a fan to ensure air flow. Be sure to brush your cat regularly in the warmer months to remove excess fur. Some cats might also enjoy playing with ice cubes on cool, hard floors.
Beware of heat stroke: Initial signs of heat stroke include heavy panting, drooling, and excessive grooming. Further signs include redness of the tongue, vomiting, and staggering. If your cat displays any of these signs, be sure to immediately cool him down by placing a cool (not cold) damp cloth on his belly. If you believe any of these signs to be extreme, be sure to seek veterinary care immediately.