Leaving a pet alone in a car has a number of potential risks. Always be conscious of the effects of heat buildup in a parked car. It only takes a few minutes for the internal heat to build up forty degrees above the outside air temperature especially if direct sunlight bakes the car. Even the cat?s body heat (expired air in the cat?s breath is 102 degrees!) will act like a heater inside the car. Leaving windows open slightly at the top surely helps IF there is a breeze. Be very cautious about leaving pets unattended in parked cars. Heat stroke is a dire emergency and one from which many pets do not recover. And you'd be shocked to find out just how fast it can happen.