The Arizona Animal Welfare League & SPCA (AAWL & SPCA) has advice for keeping pets safe in cold weather.
Outdoors can become too cold for cats, especially the late night hours. Outdoor cats seek warmth anywhere they can find it when it is cold outside. This can lead them to dangerous places, like under the hood of a car. If there are outdoor cats in your area, bang loudly on the car hood before starting the engine to give the cat a chance to escape. If you can, give them a warm place to sleep, such as a large box turned on its side and filled with an old sleeping bag or old blankets.
Dogs do have a fur coat to help keep them warm, however they feel the cold just like we do. If it is too cold for you to be out, it is probably too cold for your dog to be out. Pay attention to local freeze warnings and bring pets in when needed. Also, make sure your dog is completely dry after bathing, before spending time outdoors.
Some dogs, especially shorthaired ones, will benefit from a doggie sweater in the cold weather. Make sure your dog will tolerate a sweater and it is a comfortable fit, allowing him or her to move around freely.