We talk a lot about heat and cold, but much less about humidity. Yet, in autumn, your dog spends a good part of its days wet: rain, soaked grass, puddles, muddy paths, morning fog. This humidity affects its health in very concrete ways: its ability to regulate its temperature, its ears and paws, the parasites and bacteria it encounters during walks, its joints, and even what is in its bowl. Let's look at the body, from head to paws, to understand where humidity comes into play and how to protect against it.
Breathing: when panting is no longer enough
Unlike us, dogs sweat very little: only the glands in their paw pads produce a bit of sweat. To dissipate the heat produced by exertion, they rely primarily on panting: by breathing rapidly, they evaporate water from their tongue and respiratory tract, which cools them down. However, evaporation depends on air humidity: the more the air is already saturated with water, the less effective it is.
We tend to think this problem disappears with summer. That is not the case. Mild and humid autumn days, with 18 to 20°C, low clouds, and humidity near saturation after rain, are enough to cause difficulty for a running dog. A British study of records from hundreds of veterinary clinics (Hall et al., 2020) showed that physical exertion is the leading cause of heatstroke in dogs, and that these cases occur year-round, not just in July. Autumn is precisely the season when canicross, long walks, and ball games resume after the summer break.
What to do: in mild and humid weather, reduce the intensity of sessions and increase the number of breaks. Noisy panting that does not subside after a few minutes of rest is a warning sign. Upon returning, leave fresh water available: a dog that has panted for a long time has lost a lot of water through breathing. An anti-spill bowl keeps water clean and accessible, even with a dog in a hurry to drink, and limits splashes on the floor.
Not all dogs regulate their temperature the same way
When faced with heat or humid cold, age and health status change everything.
- The puppy does not yet regulate its temperature well. It is small, so it loses heat quickly, and it does not pace its exertion. After an outing in the rain, dry it off and let it warm up in a quiet spot.
- The senior dog often has less muscle mass, and muscles produce a large part of the body's heat. It cools down faster when wet and recovers less effectively after exertion in heavy weather.
- Small dogs and short-haired dogs have a large skin surface area relative to their volume: a soaked Chihuahua cools down much faster than a Shepherd.
- Short-snouted dogs (Bulldog, Pug, Boxer…) pant less effectively due to their narrow airways. They are more vulnerable as soon as the air is humid.
- Overweight dogs are insulated by their fat and heat up faster during exertion.
- Sick dogs are also more fragile: heart or respiratory disease limits their ability to dissipate heat, and hypothyroidism often makes dogs sensitive to the cold. Some medications also affect thirst or tolerance to exertion.
For these profiles, the rule is simple: shorter outings, careful drying upon return, and a watchful eye on their breathing.
Ears: the ideal breeding ground for ear infections
Otitis externa is one of the most frequent reasons for veterinary consultations in dogs. A large British study (O'Neill et al., 2021) estimates that about 7% of dogs suffer from it each year. Dogs with floppy ears, such as Cocker Spaniels, Bassets, or Retrievers, are significantly more exposed.
A dog's ear canal is long and angled. Humidity that enters it is difficult to drain. And in autumn, it comes from everywhere: showers, soaking high grass brushing against the ears, shaking off in puddles. Body heat, humidity, and lack of air create an ideal environment for the yeast Malassezia and certain bacteria.
Signs: head shaking, scratching, unpleasant odor, redness, or dark brown earwax.
Prevention: after a walk in the rain, dry the entrance of the canal and the ear flap with a compress. If your dog has recurring ear infections, ask your veterinarian for a drying ear cleaner. Never use cotton swabs, which push debris further in. For long-eared dogs, a shallow bowl, like the anti-spill bowl, also prevents ears from soaking in water every time they drink.
Paws: maceration between the toes
Soaked autumn ground maintains permanent humidity between the toes. The skin macerates, weakens, and becomes an entry point for yeasts and bacteria. Mud adds small gravel, grass awns, and debris that cause irritation. One may then observe red spaces between the toes, insistent licking of the paws, and sometimes a characteristic odor.
After every muddy outing, rinse the paws with clear water, then dry them, ensuring you spread the toes well. Trim hair that is too long under the paw pads: it retains water and mud. Keep a towel in the car: our article on protecting the car from dog dirt offers other tips for returning from muddy walks.
Everyday gear: drying quickly, washing easily
We rarely think about it, but the collar and leash get wet on every autumn outing. A soaked fabric collar remains damp against the skin of the neck for hours, accumulates mud, and eventually starts to smell. It is uncomfortable for the dog and is an environment favorable to bacteria.
It is for this reason that we manufacture our collars, leashes, and long lines in Biothane® and Hexa in our workshop in Bergerac, in the Dordogne. These materials are waterproof and rot-proof: they absorb neither water, nor mud, nor odors. Biothane® does not harden when drying, unlike leather, and a simple rinse with clear water or a wipe down is enough after a walk in the rain.
- Our collars made in France are available in Biothane® for dogs over 15 kg and in Hexa, which is lighter, for puppies and dogs up to 15 kg.
- The multi-position Biothane® leash can be worn by hand, around the waist, or crossbody; its Hexa version is designed for dogs under 8 kg.
- The 5m First Hexa long line remains pleasant to hold even when wet, which matters when it drags in soaked grass.
Find the entire range in our leashes and long lines selection. And for the dog itself, a dog bathrobe quickly absorbs rainwater upon returning from a walk, before getting in the car or entering the house.
Parasites: humidity, an ally of ticks
The Ixodes ricinus tick, the most widespread in France, dries out easily. To survive in vegetation while waiting for a host, it needs high relative humidity, around 80%. This is why it is found mostly in undergrowth, woodland edges, and high grass, and remains very active during mild, rainy autumns. Another tick, Dermacentor reticulatus, responsible for babesiosis, also experiences a peak in activity in autumn.
Inspect your dog after every walk, particularly the head, ears, armpits, and the space between the toes, and remove ticks with a tick remover without crushing them.
Puddles and ditches: the leptospirosis risk
Leptospirosis is a serious bacterial disease that can affect a dog's kidneys and liver and is also transmissible to humans. The bacteria are excreted in the urine of rodents, particularly rats, and survive for a long time in fresh water and damp soil. A North American study (Ward, 2002) linked the seasonality of canine cases to rainfall: rainy periods are followed by more cases.
Yet, in autumn, puddles and ditches are everywhere, and many dogs drink from them along the way. The best way to discourage them is to regularly offer them clean water: carry a bottle during long outings and leave a bowl of fresh water available upon return. Also, check that the vaccination against leptospirosis is up to date in the health record: it is one of the recommended vaccines in France and requires annual boosters.
The bowl: a risk no one suspects
Humidity doesn't stop at the house door. Kibble stored in a damp garage, or in a poorly closed bag, can develop mold. Some produce mycotoxins such as aflatoxins, which are toxic to the liver. This risk is not theoretical: at the end of 2020, in the United States, a recall of kibble contaminated with aflatoxins was associated with the death of more than a hundred dogs.
Good habits: store kibble in its original, closed bag, inside an airtight container, in a dry and cool place. Do not mix a new bag with the bottom of the old one. Discard any kibble with a musty smell or showing whitish or greenish traces.
Humid cold and joints
Many owners of senior dogs observe it: in cold and humid weather, their companion gets up with more difficulty, hesitates before stairs, and takes longer to "get moving." What does science say?
Humidity does not cause osteoarthritis. Osteoarthritis is a progressive wear of the cartilage. A British study involving more than 450,000 dogs followed in clinical practice (Anderson et al., 2018) estimates that about 2.5% of dogs receive this diagnosis each year, and the proportion increases significantly with age and weight. Its true risk factors are known: age, hip or elbow dysplasia, a previous joint injury, and especially being overweight. In a landmark study conducted on Labradors throughout their lives (Kealy et al., 2002), dogs fed in controlled quantities developed osteoarthritis later and lived nearly two years longer (median lifespan) than their siblings fed ad libitum.
On the other hand, humidity can accentuate discomfort. In humans, results are mixed: a European study conducted on elderly people with osteoarthritis (Timmermans et al., 2015) observed a modest link between joint pain and humidity, especially when associated with cold, whereas a large American study (Jena et al., 2017) found no link between rainy days and consultations for joint pain. In dogs, data is lacking. But several mechanisms are well established: a wet coat loses a large part of its insulating power, cooled muscles are stiffer, and a dog in pain moves less when it is gray outside, which maintains stiffness and muscle wasting.
Everyday comfort makes a real difference for an old dog:
- Dry it completely upon return, focusing on the back and hips. A waterproof coat limits cooling during the walk.
- Offer it thick bedding, away from cold tiles and drafts.
- Prefer several short outings to one long walk: regular movement maintains the muscles that support the joints.
- Watch out for slippery floors: wet paws on tiles cause slips and awkward movements. A mat at the entrance helps a lot.
- Monitor its weight: every extra kilo weighs on already fragile joints.
A limp, difficulty getting up, or a dog that no longer wants to jump into the car warrant a consultation. Today, there are effective treatments for pain related to osteoarthritis, and the sooner they are implemented, the more mobility the dog retains.
In summary, the steps that count
- In mild and humid weather, adapt exertion and monitor panting.
- Adapt your outings to your dog's age and health.
- Dry it thoroughly after the rain, including ears, paws, and hips.
- Choose a collar and leash that dry quickly and rinse easily.
- Inspect it for ticks after every outing.
- Offer it clean water rather than puddle water, and check the leptospirosis vaccination.
- Store kibble in a dry, airtight container.
Autumn is also the season of molting: find our advice on how to brush your dog properly during molting.
This article is for informational purposes and does not replace the advice of your veterinarian.
Sources: Hall E.J., Carter A.J., O'Neill D.G. (2020), Dogs Don't Die Just in Hot Cars — Exertional Heat-Related Illness (Heatstroke) Is a Greater Threat to UK Dogs, Animals; O'Neill D.G. et al. (2021), Frequency and predisposing factors for canine otitis externa in the UK, Canine Medicine and Genetics; Ward M.P. (2002), Seasonality of canine leptospirosis in the United States and Canada and its association with rainfall, Preventive Veterinary Medicine; Anderson K.L. et al. (2018), Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care, Scientific Reports; Kealy R.D. et al. (2002), Effects of diet restriction on life span and age-related changes in dogs, JAVMA; Timmermans E.J. et al. (2015), The Influence of Weather Conditions on Joint Pain in Older People with Osteoarthritis, The Journal of Rheumatology; Jena A.B. et al. (2017), Association between rainfall and diagnoses of joint or back pain, BMJ; U.S. Food and Drug Administration, recall of kibble contaminated with aflatoxins (2020-2021); ESCCAP France, canine ticks.