Keep pets indoors and warm
Don't leave dogs or cats outdoors when the temperature drops. Regardless of the season, short-haired, very young, or old dogs and all cats should never be left outside without supervision. Dogs and cats are safer indoors, except when taken out for exercise. During walks, short-haired dogs may feel more comfortable wearing a sweater.
No matter what the temperature is, wind chill can threaten a pet's life. Pets are sensitive to severe cold and are at risk for frostbite and hypothermia when they are outdoors during extreme cold snaps. Exposed skin on noses, ears, and paw pads can quickly freeze and suffer permanent damage.
Help neighborhood outdoor cats
If there are outdoor cats, either owned pets or community cats (ferals, who are scared of people, and strays, who are lost or abandoned pets) in your area, remember that they need protection from the elements as well as food and water. It's easy to give them a hand.
Be careful with cats, wildlife, and cars
Warm engines in parked cars attract cats and small wildlife, who may crawl up under the hood. To avoid injuring any hidden animals, bang on your car's hood to scare them away before starting your engine.
Protect paws from salt
The salt and other chemicals used to melt snow and ice can irritate the pads of your pet's feet. Wipe all paws with a damp towel before your pet licks them and irritates his/her mouth.
Avoid antifreeze poisoning
Antifreeze is a deadly poison, but it has a sweet taste that may attract animals and children. Wipe up spills and store antifreeze (and all household chemicals) out of reach. Coolants and antifreeze made with propylene glycol are less toxic to pets, wildlife, and family.
Look for tread wear
Thoroughly wipe your pet's paws and belly with warm water when she comes in, just in case she's picked up road salt, antifreeze, or other chemicals that she might lick off. (Salt can cause gastric distress in animals.) Also look for cuts from encrusted snow or ice, and remove ice balls from between foot pads. Avoid using salt-based melting products on your own property; switch to sand, cat litter, or an animal-safe de-icer. Make sure you rinse and dry your dog's feet after every walk. Checking his paws regularly and trimming the hair between his toes (with blunt-ended scissors) will prevent frostbite.