Spring is almost over in Colorado, and summer is just around the corner. As temperatures rise, it is more important than ever to think of your dog's safety when considering leaving him alone in your car.

Some passionately will argue dogs should never be left alone in cars, while others will allow certain exceptions (i.e. the car is running and the air conditioner is on; the dog will be in the car for less than five minutes; or the car is parked in the shade and the windows are cracked; etc...). Others don’t seem to think the issue is even worth considering, as is evidenced by the hundreds of dogs left to die in hot cars every summer in the U.S.

While the purpose of this article is not to haggle over which exceptions are acceptable and which are not, it is intended to help conscientious people advocate for the summertime safety of dogs. Feel free to copy the bullet points in this article, print them out and stick them on the windshields of cars with unattended dogs. Information is power, so let's use it to help those who cannot help themselves.

• Unlike humans, dogs cannot cool themselves by sweating. Dogs only sweat from the pads of their feet, which do not provide the surface area or exposure to airflow necessary for effective cooling.
• Dogs cool themselves by panting. So, the hotter the environment, the less heat is removed from the dog via air flowing over its wet tongue. The closer the temperature of a car is to the dog’s body temperature, the more likely the dog is to overheat and die.
• Automobile air conditioners are not always reliable. Many cars have a mechanism that will turn off the air conditioner if the car’s engine temperature gets too high. The engines in parked cars, particularly older or poorly maintained cars, tend to get hotter when left parked and running.
• Your dog can overheat much more quickly than you may think. If the outdoor temperature is 70 degrees Fahrenheit, the temperature inside a car with the windows rolled up can reach close to 120 degrees within an hour of turning the car off. Summer temperatures in Denver frequently reach into the 80's or 90's, meaning a dog locked in the car could quickly be subjected to temperatures up to 130 or 140 degrees. A dog's normal body temperature is about 102 degrees Fahrenheit. Without adequate ventilation, they can only withstand being exposed to temperatures of 107 or 108 degrees for a short time before suffering brain damage or even death. Slightly cracking the windows may slow the rate at which the temperature inside of a car rises, but it often does little to keep the temperature to a tolerable level.
• Colorado has statutes against animal cruelty, and the city of Denver largely mirrors these statutes. Denver also has ordinances prohibiting negligently leaving an animal unattended in a car.

If you see a dog unattended in a car this summer, you should act on it immediately. Take note of the car's model, color and license plate number. Then go to the closest establishments and ask the managers to page the car's owner. If that doesn't work, your next best bet is to call the police. Police can respond much faster than most animal control departments and can quickly enter the car and save the dog.

As for your own dog, only take him with you when you are sure he will be welcome into the establishments you are visiting. If you are unsure, contact the management of the establishments and ask about their policies. There are a number of dog friendly businesses in Denver. Patronize them, and encourage other businesses to join the list. But whatever you do, don't risk your best friend's health by leaving him in a hot car. Were he to be overcome by heat, he'd have no choice but to quietly succumb to it.