Is it too hot to walk my dog? A temperature-by-temperature guide
Most of the attention about dogs and heat goes on hot cars. The warning posters, the emergency number to call, the smashed windows - all of it is about cars. It is right that the message got through. But there is a larger problem that has not.
According to a British Veterinary Association survey in 2022, 38% of UK vets have treated a dog for heatstroke after a walk. Just 9% have treated heatstroke caused by a hot car. The walk is the primary danger, not the car.
The difficult part is that heatstroke does not happen on obviously extreme days. VetCompass data from 395 UK heatstroke events shows the median ambient temperature when dogs developed heat-related illness was equivalent to around 20 to 25 degrees Celsius - what most people would call a pleasant afternoon in summer. And in a 2020 VetCompass study, 68% of exercise-triggered heatstroke cases were caused by ordinary lead walking, not running or agility. (O’Neill et al., Scientific Reports, PMC7459873) Heatstroke happens on days most people would call fine for a walk.
What follows is a guide to what the evidence says, temperature by temperature, with a named UK source for each band.
Temperature by temperature
Below 15C: safe to walk normally
No UK source identifies any heat concern below 15C for an average healthy dog. Vets Now rates this as the lowest risk band on their chart. Walk normally. (If anything, cold weather guidance is what applies at this temperature for small and short-coated breeds.)
15-19C: safe for most dogs, but be aware
Vets Now rates 16-19C as “generally safe; caution if obese or flat-faced.” Animal Friends Insurance describes this as the “monitor” band. The VetCompass heatstroke data includes events at these temperatures - in obese, brachycephalic, or elderly dogs walking in direct sun. Safe does not mean zero risk for every dog. Keep an eye on vulnerable dogs even here. (Vets Now risk chart; Animal Friends Insurance temperature guide; VetCompass PMC9144152)
20-21C: caution starts for all dogs
This is where the UK charity and vet consensus converges.
Blue Cross: “temperatures over 20C can put dogs at higher risk of heatstroke.” Scottish SPCA: “you can walk your dog at any temperature below 20C” - meaning above it carries restriction. Agria Pet Insurance: “walking above 20C should be avoided, especially long or energetic walks.” Guide Dogs UK: “temperatures over just 20C can start to have an impact.”
For flat-faced breeds - Bulldogs, French Bulldogs, Pugs, Shih Tzus, Cavalier King Charles Spaniels - 20C is not a mild threshold. A Bulldog in a controlled clinical environment developed hyperthermia at 21C while standing still with no exercise at all. (O’Neill et al., PMC7459873)
What to do: shorten walks for all dogs. Use early morning (before 8am) or late evening (after 8pm). Keep flat-faced breeds, elderly dogs, overweight dogs, and giant breeds to 10-15 minutes maximum in shade, with water available, and watch their breathing closely.
22-24C: high caution for all dogs; flat-faced breeds should not walk
Pedigree UK names 22C as potentially too hot for flat-faced, young, elderly, obese, or thick-coated dogs. Vets Now rates the full 20-23C band as 6/10 risk - “moderate risk; rigorous exercise could cause heatstroke” for any dog, not just vulnerable ones.
At 22C air temperature in direct sun, asphalt approaches 40C. That is above the threshold where extended contact risks paw pad burns. Shaded grass is a significantly safer surface than tarmac at this temperature.
What to do: healthy adult dogs of average breeds can walk but should keep to 20-30 minutes maximum on shaded grass, early morning or evening, with water throughout. Flat-faced breeds, elderly dogs, overweight dogs, and puppies: garden toileting only; do not walk. (Pedigree UK; Vets Now chart; Vets Now paw burn data)
25-27C: serious danger for all dogs
Agria Pet Insurance: “any temperature over 25C is a very definite NO for walking.” Guide Dogs UK: “when the mercury reaches 25 degrees, greater care should be taken.” Vets Now rates this band 8/10 - “extreme caution required.”
At 25C air temperature, asphalt in direct sun reaches 52C. Skin burns in approximately one minute at 52C. (Vets Now, citing Frostburg State University pavement temperature measurements) Any walk on hard surfaces in direct sun at 25C is a paw burn hazard regardless of breed.
What to do: average healthy adult dogs - toilet trips only, 10 minutes maximum, shaded grass only, do not set foot on tarmac. Flat-faced breeds, elderly dogs, overweight dogs, giant breeds, and puppies: do not walk at all. (Agria; Guide Dogs UK; Vets Now)
28C and above: do not walk any dog
All published UK sources agree at this temperature. Claygate Vets call 28C “the danger zone.” Vets Now rates 28C+ as 9/10 - “dangerous.” Animal Friends Insurance rates 24-31C as “dangerous.” At these air temperatures, tarmac in sun reaches 55-62C.
For brachycephalic breeds, the risk at 28C extends to simply being outdoors in direct sun. The gap between 21C - the temperature at which a Bulldog overheated while standing still - and 28C is just 7 degrees. On a heatwave day above 30C, there may be no safe time to walk a flat-faced dog at all.
What to do: all dogs - indoors, with shade and ventilation. Mental enrichment instead of a walk. Shaded garden access for toileting only. (Vets Now; Claygate Vets; Animal Friends Insurance; PMC7459873)
Which dogs are most at risk?
The VetCompass study tracking 395 UK heatstroke events across 905,543 dogs gives specific odds ratios compared to Labrador Retrievers. These are peer-reviewed figures from UK clinical data. (O’Neill et al., Scientific Reports, 2020, PMC7303136)
- Chow Chow: 16.61 times the heatstroke risk of a Labrador
- English Bulldog: 13.95 times
- French Bulldog: 6.49 times
- Greyhound: 4.26 times
- Cavalier King Charles Spaniel: 3.45 times
- Giant breeds over 50kg: 3.42 times
- Pug: 3.24 times
- English Springer Spaniel: 2.74 times
- Golden Retriever: 2.65 times
Why these breeds? Brachycephalic dogs pant less efficiently. Dogs cool themselves by evaporating moisture from the tongue and upper airway during panting. A compressed flat face restricts airflow through the upper respiratory tract precisely when demand is highest - as the dog heats up and tries to pant faster. Giant breeds generate more metabolic heat per unit of body surface area, so heat dissipates more slowly than in a smaller dog. Double-coated breeds retain heat in both directions: the undercoat that keeps them warm in winter traps heat in summer.
Labradors are not in the elevated risk group by odds ratio. But they produce the highest raw numbers of heatstroke cases in the UK because they are the most popular breed. No dog is immune.
Two additional factors from the VetCompass fatal outcome data: dogs aged 12 and over have 8.87 times the odds of dying if heatstroke occurs. Overweight dogs have a substantially elevated risk of severe outcomes. (PMC9144152)
Signs your dog is overheating
Early warning signs - move to shade now:
- Heavy panting significantly beyond their usual level
- Excessive drooling, thicker and stickier than normal
- Slowing their pace, stopping, or seeking shade
- Gums redder than their normal salmon-pink
- Restlessness or agitation
- Head held lower than usual
Emergency signs - call your vet immediately and begin cooling at the same time:
- Bright red gums or tongue
- Pale, white, or grey gums - this is MORE serious than red gums, not less. It means blood pressure has dropped and the dog is in shock. Many owners recognise red as a warning sign but miss pale or white gums, which signal a more advanced emergency.
- Blue or purple gums (critical oxygen deficit)
- Vomiting
- Staggering or inability to stand
- Seizures or collapse
One finding that matters more than most owners know: a 2024 UK study of canicross events found that 24.4% of dogs had a higher body temperature at five minutes after stopping exercise than they did immediately after stopping. A dog that seems to be calming down may still be getting worse. Do not wait to see if they recover. Start cooling the moment you stop. (Hall et al., Journal of Thermal Biology, 2024)
What to do if your dog overheats
The Royal Veterinary College protocol is: Cool First, Transport Second.
Cooling before reaching the vet improves survival from approximately 50% to approximately 80%. Despite this, only 21.7% of UK dogs presenting with heatstroke had been cooled by their owner before arriving at the vet. (VetCompass; RVC HotDogs programme)
Steps:
- Stop immediately. Move to shade and somewhere with airflow.
- Pour cool water over the whole body - start at the paws, then neck, armpits, groin, and belly. Soak the coat.
- Create air movement: fan, open car doors, position in a breeze. Evaporative cooling needs airflow. Water alone is not enough.
- Offer small sips of cool water. Do not force it or allow gulping while the dog is still heavily panting.
- Call the vet, even if the dog appears to be recovering.
- Transport in an air-conditioned vehicle.
Do not drape wet towels over the dog - this traps heat against the body. A wet towel placed flat under the dog on hot ground is fine; one covering the dog is not. (RSPCA guidance)
On water temperature: The RVC recommends cool tap water at around 15C rather than iced. The concern is that very cold water can cause vasoconstriction, reducing heat dissipation from the skin. A 2024 UK canicross study found no adverse effects from water as cold as 0.1C, and emerging evidence suggests cold water is safe. The key principle: act immediately, get the dog wet, and create air movement. The exact water temperature matters far less than how quickly you act.
The pavement test
Before any walk on a warm day, place the back of your hand flat on the pavement. If you cannot hold it there comfortably, it is too hot for your dog’s paws.
UK charities (PDSA, RSPCA, Guide Dogs UK, Scottish SPCA) recommend 5 seconds as the threshold. Vets Now and the Kennel Club recommend 7 seconds. The discrepancy reflects that the test was developed by US vets and was adopted by different UK organisations independently. Neither version comes from a controlled clinical burn study. Both are practical field checks based on a sound principle: human skin and dog paw pads have comparable heat sensitivity.
At 25C air temperature, asphalt in direct sun reaches 52C. At 31C, it reaches 62C. Artificial grass reaches above 60C - hotter than tarmac in all measurements in the Vets Now university experiment. Shaded natural grass at around 26C is the safest walking surface in summer. (Vets Now paw burn data)
Pavement stays hot long after the air cools. At 10pm on a day where air temperature peaked at 25C, tarmac is still approximately 30C. The Vets Now “before 8am, after 8pm” guidance is based on pavement thermal data - 8pm, not 7pm. On days where the peak exceeded 28-30C, the pavement may not be safe until 9pm or later.
Common myths
“My dog loves lying in the sun, so heat doesn’t bother them.” Dogs sunbathe to warm up, not because they are heat-tolerant. Sunbathing is not evidence of heat resilience. Some dogs will not self-regulate - they will not move to shade even when they are becoming dangerously overheated. High-drive working breeds and Huskies in particular are documented to continue exercising past dangerous temperatures without showing self-limiting behaviour.
“It’s only 22 degrees.” At 22C, Pedigree UK says the temperature may already be too hot for flat-faced, young, elderly, obese, or thick-coated dogs. The VetCompass median heatstroke temperature is equivalent to roughly 20-25C dry-bulb. The owner experiences a pleasant afternoon; the dog is walking four inches above asphalt that is approaching 40C.
“We only went for ten minutes - that can’t cause heatstroke.” Duration appears to be secondary to temperature and breed. There is no published minimum walk duration below which heatstroke cannot occur. The VetCompass data (68% of cases from ordinary walking, PMC7459873) includes no safe duration threshold at high temperatures for vulnerable breeds.
“I should shave my Husky to keep them cool.” UK vets are clear on this: shaving a double-coated dog removes a bidirectional insulating layer, increases heatstroke risk, exposes skin to UV radiation (sunburn in dogs is real), and can cause permanent coat damage. When undercoat regrows faster than guard hairs, the result is a patchy, irregular texture that some dogs never fully recover. The correct approach is regular de-shedding brushing - a slicker brush or de-shedding tool removes dead undercoat and improves airflow through the coat. A well-groomed double coat is cooler than a shaved one.
When can you walk in the evening?
Wait until air temperature has dropped below 22-24C for healthy adult dogs, and below 20C for flat-faced, elderly, overweight, or giant breeds. Then perform the pavement test before setting off.
Sniffout’s walk quality scoring shows a green, amber, and red bar chart for each hour of the day, based on apparent temperature and humidity from the hourly forecast. On hot days it identifies a specific safe early morning window rather than marking the whole day as unsuitable - useful for working out whether a 6am walk is genuinely safe for your dog’s breed.
Alternatives to walking on hot days
A mentally tired dog is a settled dog. On the days when walking is off the table, these cover the same need:
- Puzzle feeders, frozen Kongs, and licki mats: combine feeding with sustained mental effort
- Scatter feeding: hide kibble across a room or garden for the dog to sniff out
- Short training sessions: 3 to 5 minutes of focused work is more tiring than owners expect
- Garden paddling pool in full shade: cooling and stimulating; keep the water shallow enough that the dog cannot attempt to swim vigorously in it
The number most owners do not know
The threshold that matters is not 35C. It is 20C, on an average July afternoon, for the dog with the flat face, the extra weight, or the age-related reduced heat tolerance. London averages 24C in July. Birmingham 22C. Manchester 20.5C. (Met Office UK climate averages) These are not unusual conditions. These are Tuesday afternoons.
Most days in the UK are fine for walking. But the 20C caution threshold is passed on a routine summer afternoon in every English city, every year. Now you know where it is.
If you are concerned about your dog or think they may be suffering from heatstroke, contact your vet or the nearest emergency vet immediately.
Sources: British Veterinary Association survey 2022; VetCompass O’Neill et al. 2020 (PMC7303136); VetCompass O’Neill et al. 2020 (PMC7459873); VetCompass O’Neill et al. 2022 (PMC9144152); Hall et al. 2024 (Journal of Thermal Biology, DOI: 10.1016/j.jtherbio.2024.103754); Vets Now; Blue Cross; Scottish SPCA; Agria Pet Insurance; Guide Dogs UK; Pedigree UK; Claygate/Partridge Vets; Animal Friends Insurance; PDSA; RSPCA; RVC Cool First Transport Second protocol; Met Office UK climate averages