What makes a good dog raincoat is water repellency, comfort, good fit and durable materials. Look for helpful features like leash holes, adjustable straps and reflective trim for utility, comfort and safety. The best type of dog raincoat for your dog will vary depending on where and how you will use it. In warmer climates, a lightweight and breathable rain jacket is often best for comfort. Dogs in colder areas may benefit from a warmer or insulated dog rain jacket.