If the air temperature is above 85°F (29°C), most dogs are at risk during a walk, and you should take serious precautions or skip it entirely. Above 90°F (32°C), the safest choice for most dogs is to stay inside and limit outdoor time to quick bathroom breaks. But air temperature alone doesn’t tell the full story. Humidity, pavement heat, your dog’s breed, and the time of day all factor in.
Temperature Thresholds That Matter
There’s no single cutoff that applies to every dog, but general ranges help you make a quick call. Below 70°F (21°C), nearly all dogs can walk comfortably. Between 70°F and 77°F (21–25°C), most dogs are fine, though flat-faced breeds like Bulldogs, Pugs, and French Bulldogs may already need shorter outings. Between 77°F and 85°F (25–29°C), keep walks moderate and bring water. Above 85°F (29°C), limit exercise to brief, slow walks in shaded areas. Above 90°F (32°C), it’s too hot for a real walk.
Flat-faced breeds deserve special attention. Research from the UK Brachycephalic Working Group found these dogs are at least twice as likely to suffer heat-related illness compared to dogs with normal skull shapes. Some begin to overheat at temperatures as low as 70°F (21°C), which most owners wouldn’t consider dangerous. Their shortened airways make panting, a dog’s primary cooling mechanism, far less effective.
The Pavement Problem
Even when the air feels manageable, the ground your dog walks on can be dangerously hot. Asphalt absorbs and radiates heat far beyond what the thermometer reads. On a 95°F day, blacktop surface temperatures can reach 140°F, according to measurements from the University of Georgia Extension. That’s hot enough to burn skin on contact.
A simple test: press the back of your hand flat against the pavement and hold it there for seven seconds. If it’s too hot for your hand, it’s too hot for your dog’s paw pads. Concrete is cooler than asphalt but still gets dangerously warm in direct sun. Grass stays significantly cooler and is the safest surface option on hot days.
Dogs at Higher Risk
Some dogs hit their heat limit much faster than others. Flat-faced breeds top the list because of their compromised airways, but they’re not alone. Overweight dogs struggle more because excess body fat insulates heat and makes panting less efficient. Senior dogs, puppies, dogs with thick double coats (like Huskies and Malamutes), and dogs with heart or lung conditions are all more vulnerable.
If your dog is both flat-faced and overweight, the risk compounds. Obesity in brachycephalic dogs specifically impairs the cooling effect of panting. Even a collar that pulls against the throat during a walk can compress the airway enough to reduce your dog’s ability to cool down. A harness is a better choice in warm weather.
When to Walk Instead
The coolest parts of the day are early morning and after sunset. Morning is generally better because pavement has had all night to release stored heat. After sunset, asphalt can stay hot for hours, so test the ground even if the air has cooled. On extremely hot days, a 6 a.m. walk might be your only safe window.
The American Veterinary Medical Association recommends avoiding walks, runs, or hikes during the hottest parts of the day entirely. If you do go out in borderline conditions, stick to shaded routes, take frequent breaks, and bring water for your dog. Cut the walk short if your dog slows down, pants heavily, or tries to lie down in shade.
Signs Your Dog Is Overheating
Dogs overheat quickly because they can’t sweat through their skin the way you do. They rely almost entirely on panting, which becomes less effective as humidity rises. A dog’s normal body temperature sits between 100.5°F and 102.5°F. Heatstroke begins when their internal temperature hits 105°F or higher, and it can become life-threatening within minutes.
Early warning signs include heavy panting that sounds louder or more labored than normal, excessive drooling, red gums or tongue, restlessness, and seeking shade or water urgently. These are your cues to stop the walk, get to shade, and offer cool water immediately.
If your dog progresses to vomiting, diarrhea, confusion, weakness, collapse, or seizures, that’s a veterinary emergency. Move the dog to a cool area and pour cool (not ice-cold) water over their body, focusing on the neck, belly, and inner thighs. Ice water or very cold water can constrict blood vessels near the skin and actually slow cooling. Get to a vet as fast as possible.
Alternatives to a Walk
On days that are simply too hot, your dog still needs stimulation, just not the outdoor kind. Puzzle feeders, frozen treats (like a Kong stuffed with peanut butter and frozen overnight), training sessions, and indoor games like hide-and-seek can tire a dog out mentally without any heat exposure. A quick trip to a shaded yard for a bathroom break is fine, but save the real exercise for cooler conditions.
Cooling vests are another option if you need to be outside. Research from the University of Florida College of Veterinary Medicine found that specially designed evaporative cooling vests helped working dogs cool down faster after exercise, though some dogs needed more than an hour to return to normal temperatures even with the vest. They’re a useful tool, not a free pass to walk in extreme heat.
Kiddie pools in a shaded area, sprinklers, and wet towels draped over your dog can also help on hot days. Just make sure any standing water is shallow enough that your dog can stand in it comfortably, and change it regularly so it stays cool.