Not every dog needs a coat, but small breeds, short-haired dogs, older dogs and puppies feel the cold quickly.
Cool weather
On windy autumn days a light quilted jacket or a knitted jumper is enough.
Cold and dry
A puffer jacket with a fleece lining keeps the body warm. A cotton layer underneath helps to stop the coat from tangling.
Snow and wet cold
Once belly and leg fur get wet, a dog chills quickly. A four-legged thermal suit is made for days like these.
Things to watch
The garment shouldn't pinch under the front legs, and your dog should be able to sit and walk freely. Take the coat off indoors; overheating is a problem too.