When the autumn leaves start falling and frost creeps over the ground, you know it's sweater weather. Nothing beats snuggling into your favorite warm weather garment to enjoy the brisk chill. And for certain dogs who lack an insulating fluffy coat of their own, the same holds true. If your pup's been shivering in the chill, you'll want to reach for one of the best dog sweaters to keep them snuggly warm.