Seasonal shedding in double-coated dogs is triggered mainly by changing daylight hours rather than by temperature, which is why it happens on a calendar rather than in response to a warm spell. In the northern hemisphere the heavy weeks fall around March–May and again around September–November. In Australia and New Zealand the same cycle runs six months offset: roughly September–November and March–May. Indoor dogs under artificial light shed more evenly across the whole year, because the light signal they receive is flatter. Single-coated breeds — poodles, bichons, many terriers — do not blow coat at all; they shed continuously at a low rate. Knowing which of these three patterns your dog follows tells you whether to plan two intensive fortnights a year or a steady weekly routine.
Daylight, not weather
The common assumption is that dogs shed because it gets warm. If that were true, shedding would track heatwaves, and it does not. The dominant signal is photoperiod — the length of the day — detected through the eye and mediated hormonally. Temperature modulates it, but daylight sets the clock.
Two practical consequences follow. First, the heavy weeks arrive on a predictable calendar, so you can plan for them. Second, a dog that lives mostly indoors under artificial lighting receives a much flatter light signal, and sheds a moderate amount all year instead of a great deal twice a year. Owners often read that as "my dog sheds constantly" when what they mean is "my dog's seasons have been smoothed out".
| Region | Spring shed | Autumn shed | Notes |
|---|---|---|---|
| US, Canada, UK, EU | March – May | September – November | Spring shed is usually the heavier of the two: the dense winter undercoat comes out. |
| Australia, New Zealand | September – November | March – May | Same cycle, six months offset. Northern-hemisphere grooming advice is right but half a year out of date. |
| Indoor-dominant dogs, any region | Low-level, continuous | Low-level, continuous | Artificial light flattens the photoperiod signal. |
| Single-coated breeds | Not applicable | Not applicable | Poodles, bichons, many terriers: continuous low-rate shedding, no coat blow. |
What "blowing coat" actually is
A double coat is two coats. The outer layer is guard hair: coarse, water-shedding, relatively stable. Beneath it sits the undercoat, a dense woolly layer that provides insulation and is replaced seasonally. Blowing coat is the undercoat releasing more or less at once, in clumps, over two to four weeks.
The reason this defeats an ordinary brush is geometric: the dead undercoat has to travel through the guard layer to escape. A slicker moves what has already surfaced. An undercoat rake reaches beneath the guard hair and lifts it out — and the moment it does, that fur has to go somewhere. Without airflow, it goes onto the floor and into the air. This is exactly the case that grooming vacuums were designed for.
A routine that survives the heavy weeks
Outside the shed (most of the year)
- Once a week, ten minutes, deshedding head over the whole body.
- Check the usual mat sites — behind the ears, under the collar, armpits, the tail base. Ten seconds each.
- Nails every three to four weeks. A grinder files rather than cuts, which avoids the quick.
During the shed (two to four weeks, twice a year)
- Every other day, fifteen to twenty minutes.
- Work in one direction, in sections — shoulder, back, flank, hind — rather than roaming. You will actually finish the dog.
- Bathe before the heavy work, not after. A clean dry coat releases undercoat far more readily; a dirty coat felts around the rake.
- Never clip a double coat short to reduce shedding. It does not reduce shedding, it removes the insulating layer that also keeps the dog cool in summer, and on some breeds the guard coat does not grow back correctly.
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The indoor-air side of shedding season
Pet dander is skin, not hair — but it travels attached to shed coat, and it is a recognised indoor air pollutant. The Asthma and Allergy Foundation of America notes that allergies to cats and dogs affect around 10–20% of people worldwide, and dander is the main route. During a coat blow you are releasing a lot of carrier material into a closed house in the weeks when windows are least likely to be open.
Three things measurably help: capture coat at the tool rather than off the floor; groom in one room, ideally one that is easy to wipe down; and wash bedding weekly during the shed rather than monthly. None of that eliminates dander. It reduces how much of it gets distributed.
Solis Groom Pro 5-in-1 Pet Grooming Vacuum
Clipper, deshedder, grooming brush, cleaning brush and crevice nozzle on one 10,000 Pa motor. 48 dB, 2 L cup, 3 kg.
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When to stop and call a professional
- Matting close to the skin. Clipping through a mat risks cutting skin that is pulled up inside it. This is a groomer's job, not yours.
- Sudden change in shedding pattern, bald patches, or broken hair — that is a veterinary question, not a grooming one. Thyroid disease, parasites, allergies and stress all present as coat changes.
- An animal that will not settle after several patient introductions. Some dogs need a professional and sedation-free desensitisation programme; pushing through creates a dog that will never be groomed at home.
Solis Carry Case
Moulded EVA hard shell with a repositionable divider — keeps clipper heads and combs together between grooms.
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Choosing between the two machines? The Groom Pro vs Groom Max comparison covers coat type, noise and the mains-voltage caveat for buyers outside North America. Both live in the Pet Studio collection.
Frequently asked questions
When do dogs shed the most?
For double-coated breeds, in the weeks around the spring and autumn photoperiod change: roughly March–May and September–November in the northern hemisphere, and September–November and March–May in Australia and New Zealand. Spring is usually the heavier of the two.
Why does my dog shed all year round?
Most likely because it lives mostly indoors under artificial light, which flattens the daylight signal that drives seasonal coat change. Single-coated breeds also shed continuously at a low rate rather than blowing coat.
Does shaving a double-coated dog reduce shedding?
No. It removes the guard coat that regulates temperature in both directions and can permanently change how the coat regrows on some breeds. Deshedding the undercoat is the correct approach.
How often should I groom during a coat blow?
Every other day for fifteen to twenty minutes over two to four weeks, working in sections. Bathe and dry the dog before the heavy sessions — a clean dry coat releases undercoat far more easily.
Does grooming reduce pet allergies in the house?
It reduces how much dander-carrying coat gets distributed, which is not the same as eliminating allergens. Capture at the tool, groom in one wipeable room, and wash bedding weekly during the shed.
Sources
Written by the Solis Fortune editorial team. Specifications quoted are the published manufacturer figures for the products linked above; where a supplier publishes no figure we say so rather than estimate one. Regulatory summaries are general information, not legal advice — check the rules that apply where you live before you buy.