Your snowboarding wardrobe starts out with the right base layer. First thing -- get rid of cotton. Chances are any clothing in a non-snowboarder's closet that looks like it would make a good base layer is made from cotton. Cotton T-shirts, long johns, thermal shirts, underwear and socks are all out. Instead, purchase base layers designed for snowboarding or other outdoor sports. Base layers help to insulate some body heat and perform the vital function of wicking moisture away from the body. Good base layers are made of materials like polypropylene and other poly-blends, merino wool and microfleece. Match a long-sleeved shirt with either regular underwear or long johns.
Insulation is where you have the most room to play around. Insulation is just what it sounds like: extra clothing to keep you warm. Check the daily forecast and plan your insulation around the weather that's expected. Plan for the coldest weather because you can always take off a shirt if you get hot. Again, skip cotton. Materials like fleece and wool make good insulation. Shirts, jackets, vests and pants are among the options you'll have when choosing insulation. Many riders prefer to ride with just one pair of pants, so you may not want a separate base and insulating layer on the legs.
Your key pieces of outerwear are a snowboard jacket and snowboard pants. The key factors here are breathability and waterproofing, which also indicates windproofing. Breathability allows excess inner moisture and heat to escape. Both of these characteristics are often displayed using a rating from 5,000 to 30,000-plus. The higher the number the better the piece of clothing is at the given characteristic. It's always a good idea to opt for pants on the higher end of the waterproof scale, simply because even on warm, sunny days, your pants will be contacting the snow regularly. Stay dry by buying a good, waterproof pair of pants. Jackets can be purchased around the weather conditions where you ride. If it's regularly sunny and warm, opt for a less-expensive jacket on the lower end of the rating scale. If it's cold, windy and snowy, spend the money on better protection.
Gloves are your most important accessory. Be sure to find gloves that have enough insulation to keep you warm. An inner liner helps to add extra warmth and adjust the gloves to cold vs. warm temperatures. Like pants, gloves tend to hit the snow quite often, so opt for gloves with top waterproofing even if it means additional cost. Look for Gore Tex, a leader in waterproof materials. Mittens are actually warmer than gloves, but they also limit your mobility. Gloves vs. mittens is really a personal preference issue.
You spent all this time and money on the perfect snowboarding wardrobe and then you topped it off with a stretched-out pair of striped cotton ankle socks with holes in the big toe. That's not a good decision. Like your base layer, purchase socks that are made from good warm, wicking materials. Ensure they have good elasticity so they don't slide down into your boots. Purchase different weights for different conditions.
Don't forget a good winter hat that fully covers your ears. Be sure to wear goggles with a lens color that matches the light conditions of the day. Bring a face mask if you expect cold or windy conditions.