The shelter should not be so large that they cannot preserve their body heat. Bedding should be kept clean and dry. If you have a short-haired dog outside, consider a sweater for any long exposure to the elements. Shivering is the earliest indication your dog is too cold. As hypothermia progresses, the dog becomes lethargic and weak, and it's gums may turn pale or bluish.
Frostbite is dangerous because it normally goes unnoticed beneath fur.
It affects ears, feet, tail, scrotum and mammary glands. After the initial numbness, pain and skin sloughing may occur. Don't leave your dog outdoors after cold-weather exercise. Dry your dog off and bring it indoors and let it rest and get warm. Another winter hazard to pets is antifreeze , which is extrememly toxic.