The temperature that is too cold to walk a dog can vary based on the dog's breed, size, age, and health. As a general rule, most experts advise that if it's too cold for you to be outside comfortably, it's probably too cold for your dog as well. For smaller breeds or dogs with short hair, they can start feeling cold at temperatures under 45 degrees Fahrenheit, and extreme caution should be exercised in temperatures below 20 degrees Fahrenheit. It's important to observe your dog for signs of cold stress, such as shivering or reluctance to continue walking, during colder weather. Additionally, if the temperature is under 30 degrees factoring in the wind chill, it's not safe for any dog to be outside for an extended period