Pet owners generally know “it’s hot, be careful,” but the actual mechanics of heat risk for dogs and cats are more specific than that, and a couple of simple, checkable rules cover most of what actually matters.
This is the single most useful, most underused rule: press the back of your hand against the pavement and hold it for seven seconds. If it’s too hot for you to comfortably keep it there, it’s too hot for your dog’s paw pads. Pavement can run significantly hotter than the air temperature on a sunny day — asphalt in direct sun can exceed 140°F when the air temperature is a “reasonable” 85°F — and paw pad burns are a genuinely common, genuinely preventable summer vet visit.
Dogs primarily cool themselves through panting, not sweating (they have only a limited number of sweat glands, mostly in their paw pads) — a far less efficient cooling mechanism than human sweat evaporation, especially in humid conditions where panting struggles the same way human sweat evaporation does. This means the same heat index math that applies to humans — humidity making heat dramatically worse, not just temperature alone — applies even more sharply to dogs, particularly short-nosed (brachycephalic) breeds like bulldogs and pugs, whose airways are already less efficient at moving air.
A “manageable” 85°F day for a human can be a genuine heatstroke risk for a dog, especially a short-nosed breed, especially with real humidity in the mix.
Even with windows cracked, a parked car’s internal temperature can climb dramatically within minutes — studies have measured a car’s interior temperature rising over 20°F within the first 10 minutes on a warm day, even with outside temperatures that don’t feel dangerous. This isn’t a “only on the hottest days” rule; it applies on a lot of ordinary warm days that don’t feel extreme from outside the car.
Heavy panting that doesn’t ease up, excessive drooling, bright red gums, disorientation, or vomiting are all signs it’s time to get the animal to shade, offer water, and — for anything beyond mild — get to a vet. Heatstroke in pets can escalate fast, and by the time obvious distress shows, real damage may already be underway.
Two simple, checkable rules cover most hot-weather pet risk: the seven-second pavement test before a walk, and never leaving a pet in a parked car, even briefly, even with the windows cracked. Both are easy to check, and both are responsible for a large share of preventable heat injuries.