Her coat runs on daylight, not on temperature. Photoperiod — the changing length of the day — is the signal a cat's coat evolved to follow, because day length predicts the season reliably while a warm week in early spring does not. As days lengthen, follicles release the dense, soft undercoat that insulated her all winter, making room for a lighter summer coat; as days shorten in autumn, the process runs the other way, the summer coat sheds out and the heavier winter insulation grows through. Each renewal concentrates loose fur into a wave lasting a few weeks, which is why the house seems to fill with hair all at once rather than gradually, twice a year, at roughly the same points in the seasons.
Indoor cats and blurred edges
A cat who lives under artificial light still answers to the rhythm, but less crisply. Evening lamps stretch her perceived day, heating flattens the temperature difference her ancestors also read, and the result is often a cat who sheds noticeably all year with two unmistakable peaks on top. That pattern is normal for indoor life and not a sign the cycle is broken; judge it by whether the peaks still arrive in spring and autumn, not by whether the quieter months are entirely fur-free.
Brushing through the wave
While a wave peaks, brush her daily in short sessions, always working down to the skin in sections so the brush collects the undercoat that is actually letting go, rather than skimming guard hairs off the top. Short sessions matter: five unhurried minutes daily removes more loose fur across a week than one long weekly struggle she resents, and daily collection is what keeps the volume manageable, because undercoat released overnight is either in tomorrow's brush or on tomorrow's sofa. Pay extra attention behind the ears, along the back and over the hips, where released undercoat lodges in drifts.
There is a digestive reason to keep up as well. Loose fur she does not shed onto your brush, she swallows: self-grooming during a heavy wave passes large quantities of dead hair through her stomach, and hairballs become a seasonal feature of exactly these weeks. Brushing her daily is one reliable way to reduce how much hair she has to process herself.
Loose fur around the home
Contain what escapes with placement rather than effort. Washable throws over her favourite sleeping and sitting spots gather the fallout into items that go straight into the wash, and they protect the furniture underneath during the worst weeks. A vacuum pass over her main routes and resting places every couple of days during a peak does more than a heroic weekly deep clean, because fur migrates: it works into carpet pile, under appliances and along skirting, and each day's layer weaves into the last. Keep a lint roller by the door for clothes on your way out, close wardrobe doors against a cat who would love to nap on dark jumpers, and brush her before she settles on clean bedding rather than after she has decorated it.
Shedding that is not seasonal
A normal wave is symmetrical, itchy-free and temporary: the coat thins evenly, the skin beneath looks calm, and growth replaces what left. Bald patches, broken skin, relentless scratching, shedding localised to one area, or a wave that never ends and leaves the coat visibly thinner are a different picture, and skin conditions, parasites, nutrition and internal health are among the possibilities a vet would investigate. Seasonal shedding also follows the daylight pattern — a sudden heavy shed far outside spring or autumn, especially after a move, an illness or a major change at home, is worth mentioning at her next appointment even if her skin looks fine.
Furniture stays ahead of the wave when brushing turns rotate weekly and each finished session is ticked off in KinsLe within the rota kept by Care Teams.