It is too cold for a dog to be outside if the temperature would be uncomfortable for a person to be outside for the same amount of time. The fur of a dog provides only a light layer of protection against the elements, and the wind chill makes it feel even colder to a dog left outdoors. A dog's ability to adjust to cold temperatures also depends on other factors, like the dog's amount of body fat, general health, activity level and age.
Some dog breeds are equipped to handle cold weather better than others. Dogs with a thin layer of hair are more susceptible to chilly temperatures. Dogs with short legs get colder faster because their bodies are closer to the ground. A dog that has diabetes, kidney disease, hormonal imbalances or cardiovascular problems has higher difficulty regulating its body temperature in frigid conditions.
The winter season is potentially dangerous for dogs left outside, so owners must use common sense and assess their pets' unique needs and vulnerability. When the temperature is below freezing, dogs must definitely be brought indoors. Leaving an animal outside for extended periods of time in cold conditions can lead to severe illness or even death. It is a crime to subject animals to extreme weather, and owners who break the law face large fines and jail time.