It's the last week of July, it's ninety-something degrees, the air conditioner hasn't shut off since June, and there is somehow more dog hair on the couch than there was two months ago. You vacuum Saturday; by Tuesday there's a fresh drift of it under the coffee table. Nothing about your dog has changed — same food, same walks, same everything.
This is one of the questions we hear most at the salon at this time of year, and the answer surprises almost everybody: your dog is shedding more in August because the days are getting shorter. The fall coat blow doesn't wait for fall weather. It runs on daylight, and here in St. Charles the daylight started leaving back in June.
It's the calendar, not the thermostat
The Merck Veterinary Manual puts it plainly: dogs normally shed in early spring and early fall, and they shed in response to changes in temperature and in the amount of sunlight. That second half is the part nobody expects. Coat cycles are driven substantially by photoperiod — the length of the day — not just by how hot it feels outside.
And our days have been shrinking for a while now. At our latitude, the longest day of the year runs a shade under fifteen hours of daylight. By the end of August we're down to about thirteen. That's roughly an hour and forty-five minutes of daylight gone while the forecast is still calling for heat advisories. Your dog's coat noticed. You noticed the fur. Missouri weather is the last one to get the memo.
Your dog isn't just dropping a coat — they're building one
The spring shed and the fall shed feel identical on your floor, but they're doing opposite jobs. In spring, a double-coated dog dumps the dense winter undercoat that kept them warm. In late summer, they're clearing the summer coat to make room for the winter one coming in underneath.
The Merck manual describes the difference in the coats themselves, and it's not what most people picture: the cold-weather coat of many dogs is longer and finer, which helps conserve heat, while the warm-weather coat has shorter, thicker hairs and fewer secondary hairs. So the fall blow isn't your dog "losing their summer coat and being cold." It's a swap — one coat structure trading out for another, and the loose hair on your rug is the changeover.
Which means the fur you're seeing now is the front end of this, not the back end — it generally gets more noticeable through September and into October, not less.
Which dogs actually blow coat (and which ones just look like they do)
The dramatic version belongs to double-coated breeds. The American Kennel Club describes a double coat as two layers — a dense, soft undercoat beneath a longer layer of guard hairs. That undercoat is what comes out in handfuls. Around here that's a lot of dogs: Labs, Golden Retrievers, German Shepherds, Huskies, Corgis, Australian Shepherds, Bernese Mountain Dogs, Great Pyrenees.
Single-coated dogs — Poodles, Yorkies, Maltese, Shih Tzu — don't blow coat this way. Doodles are the wild card, since a doodle can inherit anything from a low-shedding single coat to a genuinely double-coated one, and the texture often shifts as they mature.
Short-haired dogs shed too, they just do it invisibly until you sit down. Our own two are the example: Blue's a Dachshund and Belle's a Weimaraner, so neither blows coat like a Husky — which we feel smug about right up until somebody wears black pants to the couch.
What a Missouri summer does to the coat underneath
Here's the part that makes the fall shed different in our part of the country. A coat that's spent June and July in Missouri humidity has been through a lot: pond swims and pool afternoons, sweat and dust from the trail, a bath at home that got the top layer clean but never dried all the way down to the skin. Loose undercoat that was already dead in June never fully came out — it packed down and stayed there, held in place by the guard hairs above it.
Then the fall blow starts pushing more dead coat up into that same packed layer. What you get is felting: a dense mat forming from the skin outward, under a coat that still looks fine from the top. Owners are genuinely blindsided by this, because they've been brushing. The trouble is that a brush that only skims the guard hairs isn't reaching the layer where the problem lives.
If you run your fingers down to the skin behind the ears, in the armpits, along the britches on the back legs, and at the base of the tail, and it feels solid instead of springy, that's what you're feeling. Worth catching now rather than in October.
The back-to-school squeeze
The other thing that lands in mid-August around here has nothing to do with biology. School starts, and the household routine that had room for a fifteen-minute brush-out on a slow summer evening gets replaced by homework, practice, and a 6:30 a.m. alarm.
So the coat blow ramps up in exactly the weeks the brushing schedule falls apart. That's not a moral failing, it's a calendar collision — but it's why so many September appointments turn into a bigger job than the owner expected. If you know your fall is about to get busy, front-loading a little coat maintenance now pays for itself.
What actually helps at home
The tool matters more than the effort. AKC's shedding guidance points to undercoat rakes and de-shedding tools as the useful ones during heavy shedding, worked in the direction of hair growth with gentle pressure. A slicker brush afterward smooths the guard coat and picks up what the rake loosened. A few things that make a real difference:
- Work in sections, down to the skin. Part the coat and brush from the skin outward rather than raking across the top of it. The top of the coat is not where the dead undercoat is.
- Hit the spots that hide it. Behind the ears, the chest, the armpits, the rear britches, the base of the tail. These are where felting starts and where the brush usually doesn't go.
- Dry all the way down. This is the Missouri-specific one. After a swim or a bath, a coat that's damp at the skin is the setup for both matting and skin trouble. Air-drying a thick undercoat in August humidity mostly doesn't work.
- Little and often beats one heroic session. Ten minutes a few times a week gets further than an hour once a month, and your dog tolerates it better — which matters more than people think. Our post on brushing your dog between grooms goes deeper on technique.
A professional de-shed does the part that's genuinely hard to replicate at home, which is the bath-and-high-velocity-dryer combination: warm water and a de-shedding shampoo release the dead undercoat, and the dryer lifts it out from the skin in a way dry brushing can't. On our end, de-shedding is built into a full groom and the de-shedding bath rather than being an add-on line item.
Thinking about shaving to get ahead of it?
Every August somebody asks whether it'd be easier to just take a double coat down short and skip the whole thing. It's a fair question, and it deserves a real answer rather than a lecture — there are trade-offs either way, including how a double coat regrows, what it does for temperature regulation, and sun exposure on the skin. We laid the full case out, with the AKC's veterinary guidance, in our guide to shaving a double-coated dog in Missouri summer.
The short version: it's your dog and your call. Bring it up when you come in, and we'll tell you what we're seeing in that particular coat and what your options look like. Anything medical is a question for your vet, who's actually examined the skin.
When shedding isn't the season
Seasonal shedding is thinning all over, evenly, on a dog whose skin looks normal underneath. It should not leave bald patches. AKC's shedding guidance and veterinary sources are consistent on this point: bare spots, raw or inflamed skin, a sudden dramatic change, or shedding paired with itching, odor, or scabbing are reasons to call your veterinarian, not reasons to buy a better brush. Hair loss has a long list of medical causes and none of them get sorted out at a grooming table.
If something in a coat looks off to us, we'll say so — but a groomer isn't a diagnostician, and we'd rather you had your vet look at it than take our word for it.
Getting ahead of it
August fur on the furniture is the shed announcing itself early — the heavier weeks are still ahead, and a coat that gets attention now is a far easier job than the same coat in October. If you want a hand with it, book with us in St. Charles and we'll get the loose coat out of your house and into ours. For the other end of the cycle, our spring shedding guide covers the March-and-April version of the same story.
Why is my dog shedding so much in August?
Because the coat cycle responds to daylight, not just heat. Days here have been getting shorter since late June — about an hour and forty-five minutes' worth by the end of August — and the Merck Veterinary Manual notes that dogs shed in response to changes in both temperature and amount of sunlight, typically in early spring and early fall. The weather is lagging behind the calendar.
Do all dogs blow their coat in the fall?
No. The heavy seasonal blow belongs to double-coated breeds, which the AKC describes as having a dense undercoat beneath a layer of guard hairs. Single-coated dogs like Poodles, Yorkies, and Maltese don't shed that way. Doodles are unpredictable, since coat type varies enormously from dog to dog even within a litter.
How long does the fall shed last?
It varies a lot by dog, and it's less like a tidy two-week event than a ramp. For most double-coated dogs around here it becomes noticeable in late summer and runs through the fall as the winter coat comes in. Breed, age, whether the dog lives mostly indoors, and how much brushing they get all change how dramatic it looks.
Will shaving my dog stop the shedding?
It doesn't stop shedding — the same hair comes out, just shorter. There are also real trade-offs to taking a double coat down, which we cover in detail in our post on shaving double-coated dogs. It's genuinely your decision to make; bring it up at the appointment and we'll walk through what we're seeing in your dog's coat, and check with your vet on anything health-related.
How often should I brush during a coat blow?
More often and for less time is the general rule — short, frequent sessions beat one long one, both for results and for your dog's patience. Use an undercoat rake or de-shedding tool worked in the direction of hair growth, as the AKC advises, and get down to the skin in sections rather than skimming the top of the coat.
When is shedding a reason to call the vet?
Bald or thin patches, red or inflamed skin, scabbing, a strong odor, constant itching, or a sudden dramatic change in how much your dog is shedding. Normal seasonal shedding thins the coat evenly and leaves healthy skin behind. Anything outside that is a veterinary question.