It's important to monitor all dogs that are wearing coats or sweaters carefully for signs of overheating; dogs already have a layer of fur, and many healthy, medium-sized dogs will be just fine in weather that isn't too cold. While your pup is all jacketed up, check for excessive panting or scratching at the piece of clothing -- that's an indication that your dog isn't too thrilled with his or her new duds. You want to avoid discomfort, so be careful while shopping for that jacket or sweater.
When selecting doggie outerwear, it's important to look for apparel that covers the neck and belly, leaving the legs free to move (unless your dog is particularly sensitive to the cold, and needs leg coverage as well). As for material, it's best to try different kinds and see what your dog likes best. A good blend of washable wool and cotton or acrylic is a good bet to avoid itching, according to PetMD. It's a good idea to make sure the jacket is waterproof, too, especially if you live in a rainy or snowy spot. If your dog is prone to chewing or swallowing small objects, look for a coat without zippers or ties that could fall off and be gobbled up.
One technique to judge whether your pooch likes his jacket is to try it on him for a few minutes inside -- if he resists or freezes in place, then that model is probably not a good choice. Your dog should be able to walk and run freely and comfortably, with enough room to move around the leg holes. If you notice any chafing or dry spots on your dog's body, it's time to look for a new model.
And what about those silly-looking, oft-ridiculed booties that some owners put on their dogs' feet?