Your layers are on, your skis are in the car, and you’ve filled a thermos with coffee for the drive. But just as you go to lock the door, you lock eyes with your pup.

Are you really going to leave me here? All alone? she says.

Next thing you know, you’ve loaded four more legs to the car and you’re stopping for a pup cup on the way to the hill.

Trust us, we know how guilt-inducing those doe eyes are, but is it really safe to leave your hound hanging in the car while you rip laps at A-Basin? We sat down with two Colorado veterinarians—Dr. Amanda Cavanagh, who runs the small animal emergency department at Colorado State University, and Dr. Amelie Legg, a veterinarian at Willits Veterinary Hospital in Glenwood Springs—to discuss if (and how) we can keep our furry friends comfortable in the car.

Consider the Weather

A dog’s core body temperature should hover somewhere between 99 and 102.5 degrees, Legg says. Anything below that puts man’s best friend into a state of hypothermia. Unless you have a state-of-the-art sprinter van or a temp-controlled electric car, most vehicles don’t have good insulation, which means the cabin of your ride will quickly equilibrate with the outside temperature once you shut it off.

Although both vets agree there isn’t a specific temperature they deem “too dangerous” for leaving your dog in the car, Cavanagh offers an alternative way to think about it: “If the scenario feels uncomfortable for a person to have to do, I think it’s the same for our dogs.” In other words, if you wouldn’t want to sit in a 30-degree car wrapped in a single blanket, your doodle probably doesn’t either.

And hypothermia isn’t the only danger. “Specifically in Colorado, it’s so dry, and the sun being so hot, I feel like you also have to worry about hyperthermia in dogs being left in the car just as much as them becoming too cold,” Legg says. While you might enjoy skiing in this unseasonably warm winter, sunshine poses a special risk to our furry family members in the backseat. “If the car is directly in the sun, it can create a sauna-type of effect, especially because dogs are really good at generating body heat through panting,” she says.

Even when the outside temperature is below 70 degrees, the inside of your car can reach over 105 degrees, according to Prisma Health. Legg recommends cracking a couple windows if you’re skiing on a warm spring day.

Consider the Breed

French bulldog in a coat
Getty Images

Some breeds are naturally more tolerant of the cold than others. Northern breeds like huskies, Alaskan malamutes, and Samoyeds have thick, double coats that offer natural insulation. Small, thin-haired breeds like Jack Russell terriers and French bulldogs have to rely on shivering or curling into a ball to generate and conserve heat. If it’s below freezing and you have to bring along your thin-coated dog, Legg suggests dressing them in booties and a jacket to help them stay warm.

Read More: How Cold Is Too Cold to Take Your Dog Outside?

Whether your ski buddy is a Bernese mountain dog or a Boston terrier, make sure they have access to water and don’t have access to any doggy don’ts (think: pot brownies or the chicken wings in your cooler). Legg recommends checking in on them every hour to make sure they aren’t getting too cold or hot (or into any mischief). “If someone is trying to ski from start to finish—you know, first-to-last-chair situation—I don’t think it would be very fun to have your dog with you,” Legg says.

Be Cautious With Heat Sources

While it might seem like a good idea to wrap your dog in a heated blanket or set up a portable heater in the trunk, both veterinarians caution against this. “Whatever heat source you bring, you want the pet to be able to move away from it,” Legg says. If your canine can’t get out from underneath the electric blanket or tuck his tail away from the heater, he can sustain burns. And that could be the least of your worries with a portable heater.

“We don’t want, you know, a blanket caught on fire because the dog is digging around in the bedding,” Cavanagh says. “So that’s my biggest fear there—is that simply, they’re gonna burn themselves or burn the car down.”

Instead, Legg suggests creating a nest with blankets and an area without them so your dog can choose where to lie down based on his body temperature.

Watch for Signs of Hypo- and Hyperthermia

When you swing by your Subaru to check on your pet, look for signs that your dog is too cold (or too hot). Signs of hypothermia include shivering, lethargy, pale or blue gums, shallow breathing, and dilated pupils. If your dog isn’t shivering but they’re showing other symptoms of hypothermia and cold to the touch, they’ve likely run out of energy to shiver. If you notice any of these signs, start taking steps to warm your pup up immediately: Wrap her with a blanket, put socks on her feet, and turn the vehicle’s heater on. Go directly to an emergency vet.

If your pooch is panting heavily and has bright red gums or thick saliva, these are often clues that they’re overheating. Severe hyperthermia can even cause staggering and vomiting. Use fans to cool off your dog and place cool, wet cloths on their paws, armpits, and groin. Like hypothermia, hyperthermia requires immediate veterinary attention.

Know Thy Dog

Before you drag your anxious dachshund to Aspen, think about the outing from your pup’s perspective. “I do see a lot of dogs out with their owners on vacation or in the community, and I just look at the dog and think, Gosh, he’s so uncomfortable,” Cavanagh says. “Sometimes these new environments are really anxiety-provoking for pets.” If you know your dog is sensitive to the cold or needs a puppy Prozac to endure stressful situations, it’s probably best to leave him at home.