KR Cold Weather LARPing: 101?

For underlayers, underarmour is a popular choice. Look for their cold gear stuff, as it's designed to help keep you warm while being active in the cold.
Layers are great, as what's suitable for keeping you warm on an outside hike may be too warm sitting inside by a fire. Nothing beats cloaks for having a giant portable blanket to wrap yourself up in.
Good footwear is worth its weight in gold. Keeping your feet dry is the first step in keeping them warm. And wool socks are incredibly helpful--cotton kills, and that applies to feet too. Wool is prized as a cold weather material, as it can take a lot to get it to absorb water, and it retains warmth even when wet.
Keep your extremities covered... you lose a lot of heat through your hands, feet, and head. A hat and gloves are an easy fix for that.

www.knightrealms.com/game-play/logistics...-your-character.html

Also, this is useful starter reading.

Remember that you are in the woods. Cities tends to hold temperatures due to buildings retaining heat. You don't get that in Camp Sac. Wind chill will be your greatest nemesis in terms of cold. Either sucking the moisture from your skin or warmth from your body.

Figure out first how well you deal with the cold temperatures wearing normal, non-garb clothes. If you're the type to get cold easily, then keep that in mind when you wear your garb. Don't think if you just pile on layers, you'll be warm. If your core body temperature isn't that high and your body has a hard time delivering warmth to your extremities... layering isn't going to help you.

Try to get dressed when you are feeling your warmest all over. Clothes and layers can keep the warmth in... or keep the warmth out.

Sleep with your clothes for the next day in your sleeping bag! That way, they won't be freezing when you change into them in the morning.

If your body heat isn't enough to keep you warm, chemical heat packs are a great invention. They make ones that stick to the bottoms of your socks, and keep your toes warm. And the regular ones are nice to slide into your gloves.
I know some people also use those medical back warmer sticky pad things to wear under all their layers to keep their core warm.

Another thing to remember when it's cold is to drink water. There is a major risk for hypothermia, and when exhaling, you inhale dry air and lose significant amounts of water with each breath. Also water helps to maintain your body temperature, and reduces the risk of frostbite and hypothermia. So bring a water-skin or a canteen, it will save you.