Why Hot Weather is So Dangerous for Dogs
Unlike humans, dogs cannot sweat efficiently through their skin. They regulate body temperature almost entirely through panting, which becomes progressively less effective as the ambient temperature and humidity rise. When a dog's core temperature exceeds 41°C, heatstroke sets in rapidly and can cause irreversible organ damage or death within minutes. The speed at which this can occur — even in seemingly moderate temperatures — is consistently underestimated by owners.
Heatstroke is a veterinary emergency. Understanding how to prevent it, recognise it early and respond correctly could save your dog's life.
Which Dogs Are Most at Risk?
Brachycephalic Breeds
Brachycephalic dogs — those with flat, shortened facial structures — are at significantly elevated risk in hot weather. Breeds including the French Bulldog, Pug, English Bulldog, Boxer, Shih Tzu and Cavalier King Charles Spaniel have narrowed nostrils, elongated soft palates and reduced upper airway diameter. These anatomical features make panting far less efficient, meaning they struggle to cool themselves even under mild heat stress. Owners of brachycephalic dogs must exercise particular caution and keep these animals in cool environments throughout summer.
Obese Dogs
Excess body fat acts as insulation, significantly impairing heat dissipation. Overweight dogs have a higher resting metabolic rate and put greater demands on their cardiovascular system, both of which increase heat generation. If your dog is carrying excess weight, this should be addressed year-round, but extra vigilance is needed during warmer months.
Working and High-Energy Breeds
Working dogs, sporting breeds and dogs with naturally high energy levels — such as Border Collies, Huskies, Labradors and Spaniels — may continue exerting themselves even when overheated because of their high drive and focus on activity. Owners must enforce rest breaks and keep sessions short regardless of the dog's apparent willingness to continue.
Very young puppies, elderly dogs and those with heart or respiratory disease are also at increased risk and warrant additional care.
Recognising the Danger Signs of Heat Stress and Heatstroke
Early recognition is critical. The following signs indicate your dog is struggling with the heat and needs immediate attention:
- Excessive, heavy or laboured panting that does not settle
- Profuse drooling with thick, ropy saliva
- Restlessness, agitation or apparent confusion
- Vomiting or diarrhoea, sometimes with blood
- Disorientation, stumbling or weakness in the legs
- Dark red or bright red gums and tongue — a key warning sign
- Glazed eyes or an unfocused stare
- Collapse or loss of consciousness
If your dog shows any of these signs, begin cooling immediately and contact your vet or an emergency clinic without delay. Do not wait to see if they improve on their own.
Safe Exercise Timing in Hot Weather
The single most effective way to prevent heat-related illness in dogs is to adjust the timing of outdoor exercise. Veterinary guidance consistently recommends walking dogs before 9am and after 7pm during warm or hot weather. Midday temperatures — typically peaking between 11am and 4pm in the UK during summer — should be avoided entirely for vigorous activity.
Even in the early morning and evening, keep walks shorter than usual on very warm days. Stick to shaded routes where possible and always carry fresh water. Allow your dog to set the pace and respond immediately if they begin to slow, pant heavily or seek shade.
The Pavement Temperature Test
Hot pavements are a significant and often overlooked hazard. Tarmac and paving stones absorb and retain heat, reaching temperatures far above the ambient air temperature. On a 25°C day, the pavement surface can reach 52°C — hot enough to cause burns in under a minute.
Before walking your dog on any hard surface, perform the seven-second test: place the back of your hand flat on the pavement. If you cannot hold it there comfortably for seven full seconds, it is too hot for your dog's paws. Walk on grass wherever possible, choose routes with shaded surfaces and consider protective paw wax or boots if hot pavement exposure is unavoidable.
Practical Cooling Strategies
Paddling Pools and Water Play
A shallow paddling pool filled with cool (not ice cold) water gives dogs an effective and enjoyable way to lower their body temperature. Allow your dog to stand or lie in the water at their own pace. Wetting the paw pads, belly and the area around the neck — where major blood vessels run close to the surface — is particularly effective at reducing core temperature. Always supervise dogs around water and empty the pool when not in use.
Cooling Mats
Gel-filled cooling mats provide a cool resting surface and can be helpful indoors and outdoors. They work through pressure-activated gel that absorbs body heat. Look for mats that are non-toxic and durable. Place them in a shaded area and ensure your dog always has the option to move off the mat if they choose.
Hydration and Indoor Rest
Fresh, cool water must be available at all times. Provide multiple water stations in different rooms and check them frequently during hot days. You can add ice cubes to bowls to keep water cooler for longer. Dogs that are active or panting heavily will drink considerably more than usual. Keep dogs in the coolest room in the house and use fans to maintain air circulation.
Never Leave Your Dog in a Car
This point cannot be overstated: never leave a dog in a parked car in warm weather, even briefly and even with windows cracked. The interior temperature of a car can rise from 22°C to over 47°C in under an hour. Dogs have died in cars on overcast days when outside temperatures were below 20°C. There are no circumstances under which leaving a dog in a vehicle during warm weather is safe.
If you see a dog in a car showing signs of distress, call 999 immediately. Under the law, reasonable force may be used to rescue an animal in immediate danger, but you should always attempt to contact police first and document your actions.
First Aid for an Overheating Dog
If you suspect heatstroke, move your dog to a cool, shaded area immediately and begin cooling with cool — not cold — water. Apply cool water to the neck, armpits, groin and paw pads. Use a fan if available. Do not apply ice or ice-cold water, as this causes surface blood vessels to constrict, trapping heat inside the body. Offer small amounts of cool water if your dog is conscious and able to swallow. Transport to a vet as quickly as possible, even if your dog appears to be recovering, as delayed organ damage can occur after the acute episode.