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Anytime your dog is in a car without AC, watch out for signs of heat stroke. They include excessive panting, weakness, muscle twitching and vomiting.ERIC THAYER/Reuters

We have a 2017 base-model Honda Civic with no air conditioning. We’re supposed to be going camping with our dog this week (shady spot by a creek), but I’m wondering if it’s safe to drive there with the windows down – especially in the insanely-hot weather we’re seeing. We’re trying to rent a car with AC, but rates are pretty high at the last minute. – Emma, Calgary

On a cooler summer day, you probably shouldn’t sweat it if you’re driving your dog around with no AC – as long as the windows are down.

“I’ve never seen a case of heat stroke in an otherwise healthy dog just from driving in the car with the windows open,” said Dr. Jennifer Loewen, assistant professor at the Western College of Veterinary Medicine at the University of Saskatchewan. “I would be concerned if the windows are up.”

If your windows are down, make sure your pet is in a harness so he doesn’t try to jump out the window at a light, Loewen said.

But if your dog is older, overweight, has breathing problems or is a breed with a flat or “smooshy” nose, such as a pug or bulldog, even driving with the windows down on a warm day could be dangerous.

That’s because dogs don’t cool themselves by sweating like we do, even though they have sweat glands in their paws. Instead, they cool themselves by panting. So, if they can’t breathe easily, they can’t get cool.

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So is there a temperature where it’s safe to drive a pet without AC?

“I would be very cautious the minute you’re above 18, 19, or 20 degrees Celsius, especially on a humid day,” said Dr. Ian Sandler, a Toronto-based veterinarian and member of the Canadian Veterinary Medical Association’s (CVMA) national issues committee.

Anytime your dog is in a car without AC, watch out for signs of heat stroke. They include excessive panting, weakness, muscle twitching and vomiting.

If you think your dog has heat stroke, cool water or damp towels can help cool him down – and you need to get to a vet right away.

Not safe in a heat wave

But in a heat wave – temperatures across Western Canada reached the thirties and forties last week – it’s probably not safe to chauffeur any dog without AC.

“Even if windows are down, 40 degrees is still 40 degrees,” Sandler said. “And it’s hotter in a car than outside, even if it’s moving.”

Dark-coloured cars and dark interiors absorb more heat from sunlight, so they get hotter even faster.

But what if you can’t avoid a trip with your dog? Consider starting with a car that was parked in the shade or a cool garage and driving in the early morning or late evening when it’s cooler.

“You could put little stick-on shades on the window like you do with kids,” Loewen said. “Or you could freeze some wet dog food so the dog has a cold treat if he doesn’t get motion sickness – and make sure you take breaks for water.”

Even if your car does have AC, there’s a lot of heat coming in through the windows and sunroof. So, in a heat wave, that might make it too hot for Rover in your Range Rover.

“In temperatures like these, the safest place for your pet is in the house, if it’s cool,” Sandler said. “Let him out for a few minutes to do his business, with fresh water and shade.”

When it comes to pets and heat, common sense goes a long way, said Dr. Julie Menard, assistant professor of veterinary medicine at the University of Calgary.

“People should do for their dogs what they do for themselves and their kids,” Menard said. “Who would go for a run at noon in a heat wave?”

Never safe to leave kids or dogs alone

If your car doesn’t have AC, be cautious when driving with children and seniors, said Amber Rollins, director of Kids and Cars, a U.S.-based non-profit focused on child safety, in an e-mail.

“I can think of one case where a baby died during a road trip in a vehicle without AC,” Rollins said. “Children’s body temperature rises three to five times faster than an adult’s, so what feels comfortable to us might not be safe for them.”

Battery-operated fans, wet rags and frequent breaks in places that have AC might help keep everyone cool in cars without AC, she said.

Whether you have air conditioning or not, you should never leave your child or pet alone in a car.

Air conditioning can get turned off, and without it, a parked car can quickly turn into a convection oven, even with the windows cracked open, CVMA’s Sandler said.

When the outside temperature is above the low teens, there’s no safe amount of time to leave a dog alone in a car.

“Never, ever, ever,” Menard said. “We’ve seen heat strokes on the first nice day of spring when it’s 15 to 18 degrees Celsius outside.”

The U.S. National Highway Traffic Safety Administration has said that on a 60-degree Fahrenheit day (15 degrees Celsius), the temperature inside a car can reach 110 degrees Fahrenheit (43 degrees Celsius).

On a 16-degree Celsius day in May, two dogs were in Victoria were rescued from a car that had an interior temperature of 47 degrees Celsius, even though the windows were cracked, Victoria police said.

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