Outside cats are susceptible to hypothermia and other cold-related illnesses in winter, especially during periods of rain and snow. Fortunately, it's easy to build an outside cat bed that will provide a warm, safe place for your pet to sleep at night. Cats don't care about fancy pet igloos or kennels. They just need an insulated box that blocks wind, rain and cold and contains some soft bedding.
Purchase a rectangular lidded styrofoam cooler big enough for your cat to easily fit inside and turn around.
Decide where the finished cat bed will be located. If you can find a spot that is partly sheltered --- such as a garage, porch or other covered area --- the foam cooler will probably be sufficient. If not, purchase a lidded plastic storage bin just large enough to enclose the foam cooler.
Place the foam cooler upright. Carefully cut an arched cat-size door into the container toward the bottom, using a razor knife. Err on the smaller side, as you can always enlarge the opening later if your cat won't fit. But a hole that is too big will let in unnecessary cold air, and possibly predators.
If using a plastic container, set the cooler inside the container. With a pen or marker, sketch a door that lines up with the hole in the cooler. Cut out the door using a razor knife or other sharp tool. If the plastic is too difficult to cut, direct hot air from a hair dryer onto the area for several minutes to soften it.
Add a layer of straw to the bottom of the foam cooler to provide further insulation and a soft place for your cat to curl up.
Place the foam lid onto the cooler and use a Phillips screwdriver to secure one screw in each corner. This will keep the lid from being removed by wind or other animals. Secure the lid on top of the plastic bin, if applicable.
Put the outside cat bed in its permanent location and introduce your cat to its new home.
If your outside cat is prone to fleas, add some cedar chips or dust pet-safe flea powder in with the straw.
Place the cat bed where it will be safe from flooding and snow drifts, preferably in a raised area.