It is not the outside air temperature that makes you cold, but the lack of proper clothes and skills to stay warm.
At this cold:
17.1 Be very skeptical about your cartridge-based stove such as Jetboil, etc. It may refuse to work.
17.2 Batteries discharge a lot faster, bring more extra.
17.3 Camera probably will freeze as well, unless kept next to the body.
17.4 Overnight, boots will freeze brick-solid and in the morning it will
be impossible even to work out laces. Keep boots inside your sleeping
bag. Bring 2 plastic bags for that.
17.5 Do not unfold, unzip your dawn sleeping bag until you are ready to
get inside it to sleep. Otherwise it will acquire outside temp (-25C)
and it will take you hours to get warm. This is because the purpose of
the bag is to keep the inside temperature, so ironically the better the
sleeping bag the longer it will take to get warm.
17.6 Human head is responsible for losing 30% of the body heat, so
before putting on another jacket, make sure your head is properly
17.7 Your emergency bivy can improve your sleeping bag rating by extra -3C.