This is a great tip from the AVMA:
Just like people, pets’ cold tolerance can vary from pet to pet based on their coat, body fat stores, activity level, and health. Be aware of your pet’s tolerance for cold weather, and adjust accordingly. You will probably need to shorten your dog’s walks in very cold weather to protect you both from weather-associated health risks. Arthritic and elderly pets may have more difficulty walking on snow and ice and may be more prone to slipping and falling.