A warning to everyone with a dog - NEVER EVER leave your dog in a car in warm weather , ever!! Sadly on May 28, 2009 a Rottweiler named "Buddy" was forgotten about in the back of his owners van and passed away as a result..... (see article below).
Please know your car can become a death trap in just a matter of minutes even on a MILD day with your windows open!! Once a dogs temperature reaches just 106 degrees (101 is a dogs normal temperature) their vital organs are already in serious trouble and your dog will have a heatstroke. And heatstrokes are DEADLY!
On a hot day your car will climb as fast as 30 degrees per minute and would only be a matter of a COUPLE MINUTES and your dog would be dead. For example on a 80 degree day your car can reach 120 degrees in just 10 minutes! and don't think that a 70 degree day is not hot -- your car will reach the deadly limit within 10 minutes!!
According to Dr. William Fortune, a professor at the College of Veterinary Medicine at Kansas State University, "Dogs become less efficient at cooling themselves as the humidity rises. Just like people, dogs are cooled by evaporation. The problem with high humidity is that it decreases evaporation and slows down the cooling process. This time of year we hear a lot about the heat index, which is a measurement of both the temperature and the humidity level, and that is what an owner needs to pay close attention to. There are other factors that hinder canines' ability to cool themselves. They only have sweat glands on the pads of their feet and on their nose, which are inadequate for cooling during hot and humid days. Panting helps dogs cool themselves but they still aren't as efficient at cooling themselves as people are."
If your dog has a heatstroke cool your dog down immediately and get him to a vet!
Cool him down with cool (NOT COLD) water, take him into an air conditioned area, sponge their groin area, tummy area, wet his tongue, place rolled up wet towels against his head, neck, tummy, and between his legs. When his temperature drops to 104 F or 103 F, stop cooling efforts. Cooling too fast or too much can cause other problems.
Signs of a heatstroke
PS and don't leave your dogs outside on hot summer days -- they are in serious danger of a heatstroke and they happen FAST!
See article - "A sad warning for dog owners"