Dress like a Polar Bear
Image Credit: mape_s
A Polar bear’s coat has two layers of hair: an outer layer, made up of long (5-15cm) clear guard hairs that are hollow core filled with air; and a thick undercoat, made up of shorter hair. When sunlight shines on Polar bear outer guard hairs, it causes a reaction known as luminescence and makes them look white but their hair is clear and the skin is black.
Not saying you need to wear clear clothes like the story about the Emperor’s new clothes, just referring to the layers. Your base “undercoat” close fitting layer needs to wick away moisture e.g. wool or thermal, then a middle layer to trap body heat e.g. a thin down jacket or a thin merino wool jumper. And an outer layer totally waterproof and breathable to protect from the weather (this is totally the most important layer). Repeat for the legs.
Waterproof Gloves or Mittens are a must. Always have a spare pair with you. And thick socks are better than 2 thin pairs that will bunch and scrumple and give you grief and pain. There are even heated versions https://www.ellis-brigham.com/brands/therm-ic
A woollen hat (yes under your helmet) or head scarf on hot sunny days, is also important to reduce your moisture loss and keep your brain functioning. A buff or neck scarf is also a good cold stopper. Always have one with you. And of course eye protection, googles and glasses.
Where dreams begin for outdoor adventures in the inspiring Jungfrau region