In many parts of the northern hemisphere, it’s winter, which means cooler temperatures. Even if you keep your cat indoors, you need to think about how to keep your cat warm during cold days and nights.
Outdoor cats should be kept inside as much as possible. They should also have access to shelter outside, even a heated house outside. Indoor cats can also benefit from warm blankets and a heating pad as well.
In other words, keep your cats warm and then worry about keeping yourself warm. After all, who’s more important? You or your cats?