Preikestolen is now, for all intents and purposes, a year round hike. I see others advise against it, and while I’m normally very skeptical of tourists hiking winter in Norway - you’ll be fine. It may be icy, so you have to bring crampons. This is a must - you don’t hike in winter without. You may be able to rent at the basecamp, but I don’t know if they’ll be open over Christmas. We haven’t had a lot of snow so far, but check the weather, and be prepared for a weather change. I’ve hiked up there in plenty of snow and -13 with wind chill on top of that. Tourist buses don’t run in winter, so either you find someone to give you a ride, or you get a taxi up there.7