It’s summertime and the weather is beautiful here in Portland.  But, I recently underestimated the harmful potential of even a mild summer day, on my dog.

Last weekend I ran into the store, leaving Maisey in the car. It was only about 74 degrees outside, and I left the windows cracked. I returned less than 15 minutes later to my love, panting. The second I saw her I felt horrible. The car was warm (not hot) and she was uncomfortable. I didn’t think for a second that the car would get so warm on a cool, breezy afternoon with the windows down.

I learned my lesson, fortunately not the hard way. You may not realize exactly how hot a car can get. Check out the numbers at mydogiscool.com, a program of United Animal Nations. When it’s 72 degrees, a car in direct sun can reach an internal temperature of 116. Even in the shade, a car can be 10 to 20 degrees hotter than outdoors, and cracking the window has almost no effect.

According to Veterinarian Cate Rinaldo, a volunteer with United Animal Nations, dogs don’t have sweat glands all over their bodies like humans do, so the main way they can cool off is by panting, which isn’t very efficient.

Once a dog’s body temperature gets over about 106 — normal temperature is around 101 — the result is “everything from nerve damage, heart problems, liver damage, systemic organ failure, and it happens fast, within a matter of minutes,” she says.

Even indoors, it can get too hot for some animals. MSNBC.com tells of an elderly, overweight beagle that died of heat exhaustion in his own home; sadly, the house did have central air conditioning but the owners hadn’t left it on since there were no people home.

I am very protective of my dog. I would never to anything to put her in harms way, and yet, I made this very simple mistake.

Please remind your friends and family that even on a nice day, being left in the car is not only dangerous for your pet, but could be deadly.