Well, that's a question that I can answer. A Christmas cactus is actually a tropical plant, so it's not designed to survive in cold weather. Therefore, it's not recommended to keep a Christmas cactus outside in the winter. If you have one and you want to keep it alive, you should bring it inside during the winter months. It's also important to make sure that the plant is kept in a place that's warm and humid, as it likes bright, indirect sunlight.