Yes, they are even subzero at daytime – don’t forget to bring gloves with you, when walking through. Taking pictures will freeze your hands eventually…

Yes, they do. But they provide a huge sleeping bag, under which you should wear something light (so you don’t sweat). If you sweat, it will freeze and you’ll be cold. They tell you to layer your clothes, get in the sleeping bag, take off your top layers (leaving them in the sleeping bag) and sleep with your mouth and nose outside of the sleeping bag. Any condensation or sweat will cause coldness!! If you have to go to the bathroom in the night, you put your clothes back on (they will be warm inside your sleeping bag) and then get out of the bag.. Does that make sense? I hope so. It was an amazing experience!!! (By the way, I was pregnant when I did it so I paid for a regular room just in case it was too intense…)