Summer Heat Safety for Dogs

Summer is a great time to get outside with dogs, but warm weather brings real risk. Overheating can progress to heatstroke, a life-threatening emergency that occurs more often during the hottest months and after prolonged exposure to hot or humid environments.

What Is Heatstroke?

Heatstroke is a marked, dangerous elevation in body temperature caused by prolonged exposure to hot or humid conditions, or strenuous exercise.1,2 A dog's normal body temperature falls between about 100–102°F; heatstroke sets in once temperature climbs past 104°F, the point at which the body's own cooling mechanisms become overwhelmed.1 Dogs most commonly develop heatstroke when left alone in a hot car, left outside without shade in hot, humid weather, or exercised in hot, humid conditions.1,2

Unlike humans, dogs can't sweat to cool themselves. They have only a small number of sweat glands, located on their paw pads, which provide minimal cooling. Their primary way of dissipating heat is panting, along with vasodilation and seeking shade.3 Dehydration accelerates the whole process, so continuous access to fresh water is essential whenever temperatures rise.2

Who Is Most at Risk?

All dogs are susceptible to heatstroke, but some face higher risk. Brachycephalic (short muzzle) breeds, such as Pugs, Bulldogs, Boston Terriers, and Boxers, have airway conformations that impair efficient panting and struggle more to cool themselves in hot or humid weather.4,5 Extra caution is also warranted for dogs that are overweight, elderly, have underlying heart or respiratory conditions, or have thick or dark-colored coats, all of which raise heatstroke risk.1,4

Recognizing the Signs

Heavy panting, seeking shade, whining, reluctance to play, and drooling can be early signs of overheating.1,2 At this stage, move the dog into cool, air-conditioned space with access to water right away; wetting the dog with cool water and placing them in front of a fan can also help. Double-coated breeds (Siberian Huskies, Pomeranians, Great Pyrenees, and similar) should be wet down to the skin, not just the coat surface, for the cooling to be effective.

If a dog continues to pant and drool excessively, or develops difficulty breathing, bloody diarrhea, vomiting, weakness, confusion, seizures, or collapse, these signal true heatstroke and the dog should go to a veterinary hospital immediately.1,2 Treatment often includes intravenous fluids and supplemental oxygen, and bloodwork can help assess the severity of dehydration and organ impact.2

Preventing Heatstroke

A handful of habits go a long way toward keeping dogs safe in warm weather:

  • Choose cooler times of the day for activities. The hottest stretch is often mid-to-late afternoon (roughly 3–5 p.m.), not just midday. Plan walks for early morning or evening.

  • Avoid strenuous exercise especially during the hottest parts of the day or on very humid days. Dogs need to acclimate to hotter temperatures slowly – avoid overdoing it early in the season before a dog has had a chance to get used to warmer temperatures.1,4

  • Provide shade. Always choose shaded spots when possible as staying out of direct sunlight reduces heat load significantly.

  • In extreme heat, keep dogs inside. Air conditioning and fans will help maintain a cooler indoor temperature and avoid wide swings in temperatures over the day.

  • Take water breaks often. Bring along water and a collapsible bowl on outings. Make sure each dog has an opportunity to drink often. Consider using pools to allow swimming or wet down dogs with sprinklers or hoses.

  • Watch pavement temperature. Asphalt retains heat and can be far hotter than the surrounding air. A dog's paw pads are tougher than human skin but can still burn easily when exposed to hot pavement. A suggested rule is if you can't hold your hand or bare foot on the pavement for about 10 seconds, it's too hot for a dog to walk on.

  • Never leave a dog unattended in a car. Car temperatures inside a vehicle can climb 40 degrees or more within the first 15-20 minutes even when ambient outside temperature is around 70 degrees F, and cracking the window does very little to help.6 That data comes from a pediatric vehicle-safety study, but the underlying physics of a closed car heating up applies to any occupant, dogs included. A running, air-conditioned car is not a safe substitute for not leaving a dog alone in it.

The Bottom Line

Heatstroke is preventable in the large majority of cases. Fresh water, shade, sensible timing of outdoor activity, and awareness of individual risk factors like brachycephalic anatomy, excess weight, age, and coat type are the most effective tools owners have. Any dog showing signs of heatstroke needs prompt veterinary evaluation, since early intervention meaningfully improves outcomes.1,2

Who checked this page

Laura Gaylord, DVM, DACVIM (Nutrition)

Board Certified Veterinary Nutritionist®

Last reviewed 16 September 2026.

References

  1. Bruchim Y, Klement E, Saragusty J, Finkeilstein E, Kass P, Aroch I. Heat stroke in dogs: a retrospective study of 54 cases (1999–2004) and analysis of risk factors for death. J Vet Intern Med. 2006;20(1):38–46.
  2. Johnson SI, McMichael M, White G. Heatstroke in small animal medicine: a clinical practice review. J Vet Emerg Crit Care. 2006;16(2):112–119.
  3. Robertshaw D. Mechanisms for the control of respiratory evaporative heat loss in panting animals. J Appl Physiol. 2006;101(2):664–668.
  4. Hall EJ, Carter AJ, O'Neill DG. Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016. Sci Rep. 2020;10:9128.
  5. Packer RMA, Hendricks A, Tivers MS, Burn CC. Impact of facial conformation on canine health: brachycephalic obstructive airway syndrome. PLoS One. 2015;10(10):e0137496.
  6. McLaren C, Null J, Quinn J. Heat stress from enclosed vehicles: moderate ambient temperatures cause significant temperature rise in enclosed vehicles. Pediatrics. 2005;116(1):e109–e112. (Pediatric vehicle-safety study; cited here for enclosed-vehicle temperature dynamics, not dog-specific data.)