How Cold Is Too Cold for Dogs?

When people ask how cold is too cold, they usually want a temperature. The honest answer is that a number is only a starting point. A dog's tolerance depends on how much insulation they carry, how well they are acclimatized to cold, whether they are moving or standing still, and whether they are wet or dry. A husky bred for sub-zero work can be perfectly happy at temperatures that would send a short-coated greyhound shivering back to the door.

Think of the temperature as one input alongside several others. If you use a general guide, adjust it down for dogs who are small, thin, short-coated, very young, elderly, or ill, and adjust it up for large, thick-coated, active dogs who are used to the weather. And always treat your dog's behavior as the final say: a dog who is slowing down, lifting paws, shivering, or trying to turn for home is telling you it is time to go in.

These ranges are commonly used rules of thumb. They are meant to help you think about risk, not to guarantee safety, and they assume a dry day without strong wind.

• Above 45°F (7°C): comfortable for most dogs. Very small, thin, or elderly dogs may still want a coat.
• 32 to 45°F (0 to 7°C): small, short-coated, and older dogs begin to feel the cold. A coat helps, and walks may need to be shorter.
• 20 to 32°F (-7 to 0°C): at or below freezing, limit time outside for small and vulnerable dogs, and watch all dogs for signs of discomfort. Large, thick-coated dogs are often fine for a normal walk if they keep moving.
• Below 20°F (-7°C): risk of hypothermia and frostbite rises for any dog during longer outings. Keep walks brief, protect paws and ears, and consider indoor activities instead.
• Below 0°F (-18°C): dangerous for most dogs. Keep outings to toilet breaks, and bring dogs inside quickly.

Note: These are general guidelines. Ask your veterinarian what is appropriate for your dog's breed, age, and health, particularly if your dog has a heart condition, arthritis, diabetes, or another medical issue.

Small dogs lose heat faster because they have a larger surface area relative to their body mass, and their bellies are close to the cold ground. Short-coated and single-coated breeds, such as greyhounds, whippets, boxers, chihuahuas, and many terriers, have little insulation. Dogs with very little body fat feel the cold more, and so do puppies and seniors, whose ability to regulate temperature is weaker.

Medical conditions matter too. Dogs with hormonal problems, heart disease, kidney disease, and some other illnesses can struggle to maintain body temperature. Arthritis often feels worse in the cold, and you may see stiffness or reluctance to walk. Dogs who have recently moved from a warm climate may also need time to adjust.

On the other side, northern breeds with dense double coats, such as huskies, malamutes, Newfoundlands, and Bernese mountain dogs, tolerate cold better, and may overheat quickly in a warm house. Even so, they are not invulnerable, and their paws, ears, and feet can still be affected by ice and wind.

Wind chill affects dogs as it does people. A dry, still 30°F afternoon feels very different from the same temperature with a stiff wind and rain. Wet fur loses much of its insulating value, so a dog who has been swimming, rolling in slush, or caught in sleet will get cold much faster. Dry them thoroughly when you get home, paying attention to the belly and legs.

Time of day plays a part as well. Early morning and after-dark walks are colder, and the ground can be icy. If you can, schedule the longest walk for the warmest part of the day, and use shorter trips at the extremes. Add reflective gear and a light for visibility in the dark.

Dogs usually give clear clues before things become serious. Learn them, and respond promptly.

• Shivering or trembling.
• Holding a paw up, limping, or refusing to put weight on it.
• Slowing down, stopping, or trying to turn back.
• Hunched posture with a tucked tail.
• Whining or acting anxious.
• Seeking shelter, or burrowing into you.
• Cold ears, nose, and paws.

Hypothermia happens when body temperature drops too low. Early signs include shivering, lethargy, and weakness. As it worsens, shivering can stop, muscles may become stiff, gums can look pale, breathing and heart rate slow, and the dog may become unresponsive. It is an emergency.

Frostbite affects extremities with poor circulation, such as the tips of the ears, the tail, the paws, and the scrotum. Affected skin may look pale, gray, or blue and feel cold and hard, and later become red, swollen, and painful as it thaws. Frostbite is often not obvious until a day or two later.

If you suspect hypothermia or frostbite, take your dog indoors immediately. Wrap them in dry blankets, and use warm (not hot) water bottles wrapped in towels. Do not rub frostbitten skin or use direct heat such as a hair dryer on high or a heating pad on a bare body. Contact your veterinarian right away.

Note: If your dog is collapsed, unresponsive, or breathing very slowly, go to an emergency veterinary clinic immediately, and keep the dog warm on the way.

A few habits make winter outings safer and more enjoyable. Keep your dog moving, since a brisk walk generates heat. Choose routes that avoid frozen ponds and unstable ice, and keep your dog on a leash near water. Check the pavement for salt and de-icers, and wipe your dog's paws and belly afterwards.

Consider a coat for dogs who need one, boots for dogs who tolerate them, and shorter, more frequent outings when it is very cold. On the coldest days, swap part of the walk for indoor games and training. A dog who has had mental exercise often copes better with less time outdoors.