We’re an Arizona shop, so this one is personal. Most people think of hot cars as a July problem. Here it’s closer to a year-round one: Phoenix-area highs usually stay in the 90s into October and warm right back up in spring, and plenty of winter afternoons are sunny enough to heat a closed car fast. Nobody who leaves a dog in the car “just for a minute” means any harm. They just underestimate how fast a car heats up, and how quickly a dog overheats.
A parked car heats up faster than you think
A closed car acts like a greenhouse. Sunlight passes through the glass, heats the seats and dashboard, and the heat has nowhere to go. Studies of parked cars have found the inside temperature can climb about 20°F in the first 10 minutes and keep rising from there. On a 100°F Arizona afternoon, the inside of a car can pass 140°F.
It doesn’t have to be hot outside. Because the sun does the heating, a pleasant 70°F day can push a closed car to around 90°F in 10 minutes and past 100°F in about half an hour. That’s why this matters in October, March and every sunny month in between.
Cracking the windows barely helps. The same research found an opened window changes the rate of heating very little. Parking in the shade helps a bit, but shade moves, and the air inside still gets hot.
Dogs are more vulnerable than we are because they can’t sweat the way people do. They cool themselves mostly by panting, and panting stops working when the air around them is hotter than their body.
The simple rule
If your dog can’t come inside with you, leave them at home. That includes “quick” stops for gas, the pharmacy line and the drive-through that turns out to be 15 minutes long. On warm days, many Arizona dog owners simply don’t take their dogs on errands at all.
Signs of heatstroke in dogs
Heatstroke is an emergency. Watch for:
- Heavy, frantic panting that doesn’t slow down
- Thick drool, or bright red or pale gums
- Weakness, stumbling or confusion
- Vomiting or diarrhea
- Collapse
If you see these signs, get your dog somewhere cool right away, offer small amounts of water, wet their body with cool (not ice-cold) water, and call your vet or an emergency animal hospital immediately. Heatstroke can cause serious damage even after a dog seems to recover, so get them checked.
If you see a dog in distress in a parked car, note the car’s details, try to find the owner nearby, and call 911 or local animal control.
Hot pavement: the 7-second test
Arizona asphalt in direct sun can get hot enough to burn paw pads, in summer and on plenty of spring and fall afternoons too. Before a walk, press the back of your hand on the pavement. If you can’t comfortably hold it there for 7 seconds, it’s too hot for paws. Walk early in the morning or after sunset, stick to grass and shade, and keep parking-lot walks short.
Road trips in warm weather: how to do it right
Driving with your dog on a warm day is fine when you plan for the heat:
- Cool the car first. Start the engine and run the AC for a few minutes before your dog gets in.
- Drive in the cooler hours. Early mornings are best for long drives.
- Bring more water than you think you need, and offer it at every stop. A bottle with a built-in bowl like the Portable Dog Water Bottle or the Stainless Steel Travel Bottle makes that easy, and a collapsible bowl takes no space in a bag.
- Cover hot seats. Leather and dark fabric get very hot in the sun. A back seat cover gives your dog a cooler, cleaner surface.
- Plan stops where your dog can come with you, like a shaded rest area or a pet-friendly patio, never a store where they’d wait in the car.
- Buckle them in with a seat belt tether clipped to a harness, so they stay in the air-conditioned back seat instead of climbing around.
The bottom line
Arizona heat doesn’t mean your dog has to stay home. It means you plan around the heat: cool car, plenty of water, cool hours, and never, ever a wait in a parked car.
For more on safe car rides, read our driving instructor’s checklist for traveling with your dog, or browse the Dog Travel collection.
This article is general information, not veterinary advice. If you’re worried about your dog’s health, call your vet.