Leaving dogs in hot cars is a preventable cause of extreme suffering and death, with temperatures rising rapidly to lethal levels even on mild days.
Dogs left in hot cars experience an agonizing progression from discomfort to distress to heat stroke as their body temperature rises uncontrollably. They pant frantically trying to cool down, become increasingly distressed as heat rises, and then suffer organ failure as temperatures exceed survival thresholds. Heat stroke causes brain damage, kidney failure, and gastrointestinal hemorrhage. Survivors may have permanent organ damage. This entirely preventable suffering occurs thousands of times each year.