Autumn is tougher on a coat than winter. In winter it's dry and cold, and most dogs are already wearing their thick undercoat by then. In autumn, though, everything changes within the same month: wet leaves, damp air, and right in the middle of it, the coat change, where the summer coat falls out and the winter coat grows in.
Three things that come together in autumn
Moisture that doesn't dry off. In summer, a wet dog is dry again after half an hour. At ten degrees with drizzle, that takes the whole afternoon. Damp fur that stays damp for a long time is the breeding ground for skin irritation and the classic wet-dog smell that settles into the whole hallway.
The coat change. For most dogs this happens in spring and autumn, regardless of the outside temperature, controlled by day length. If you don't brush now, your dog carries the loose undercoat around for weeks, and it matts exactly where a harness or coat rubs.
Mud and road salt arrive earlier than you'd think. By October the first wet leaves are already on the path, and anyone walking in the woods brings fine grit and soil home that settles into the undercoat.
What actually helps
Dry them off before they lie down. A towel by the door isn't a minor detail, it's the single most effective measure there is. Back, belly and especially the gaps between the paw pads, that's where moisture sits the longest.
Brush regularly, not just when you notice it. Two to three times a week is enough for most dogs, more often during the coat change itself. This removes loose undercoat before it matts, and spreads the natural oils that make the coat water-repellent.
Check the paws briefly after every walk. In autumn, more collects between the pads than usual: small stones, softened leaves, and for some dogs that's already enough to cause irritation. A damp cloth is usually enough, no elaborate washing needed.
For long-haired dogs: trim the leg hair. Not for looks, but because long hair on the legs picks up the most mud and takes the longest to dry.
When a coat actually helps
A coat doesn't replace coat care, but it shortens the time the fur is wet at all. For short-haired dogs and older dogs with thinner coats, that often makes the difference between a dry ride home and an afternoon with a damp smell filling the whole car. You'll find suitable models in our raincoat guide.
For how to find the right size, see our article Measuring for a dog coat: the two-minute guide: measure the back length and chest circumference, then the calculator tells you the right size. Between two sizes, take the larger one.