The temperature in a car can reach 100°F within 10 minutes on a 80°F day. On a 90°F day, the temperature in a car can reach 160°F in less than 10 minutes. Cracking or partially rolling down the windows has been shown to have little effect on the temperature inside a car.
Pets can suffer brain damage or die from a heatstroke or suffocation in 15 minutes. They can only cool themselves by panting and sweating through their paw pads.
Symptoms of overheating include restlessness, excessive thirst, thick saliva, heavy panting, glazed eyes, rapid heart beat, lethargy, unsteadiness, staggering gate, fever, vomiting, bloody diarrhea, and deep red or purple tongue.
To lower its body temperature move it into the shade or air-conditioned vehicle or building, apply cool (not cold) water all over its body or immerse in cool water for up to two minutes (do not use ice or cold water and do not overcool the animal), let it drink small amounts of cool water or lick ice cubes, and take it to the vet immediately.
If you see a dog in a parked car, write down the car’s color, model, make, and license plate number. Have the owner paged in nearby businesses, or call the local animal control or non-emergency police number. Have someone watch the dog…Don’t leave the scene until the situation is resolved.