Winter is cold. Do you know what material your base layer of clothing should be made out of when you're trying to stay warm in that cold? Me either, really, because it depends on the situation, and I find myself looking it up all the time!! I've posted before about how to staying warm in the winter (http://www.vingle.net/posts/535275) but that card focused on what layers you need to focus on. Today, I wanna talk about what your base layer should be made of! Base layers are key for temperature regulation. While they won't provide you the insulation you need to stay warm, the point of wearing certain base layers is to (1) wick your sweat away from your skin if you work up a sweat (so you stay dry) and to (2) keep you warm when you're staying still. Different types of base layers will do that to different extents, and in different ways. Synthetic made base layers wick dampness very well, dry very fast, and keep you warmth in a breathable well, but they stink. Horribly. Cotton should be avoided, as it has a tendency to retain moisture, and then become cold when you stop moving or the temperature drops. Silk is great to wear under casual clothing,as it is thin and warm, but it's not so great for moving between cold/warm temperatures, such as when bundling up before heading to the warm office. Lastly, and my favorite, Merino wool: it wicks well, it warms well, and it never smells. A really fantastic choice. So, what should you use? Well, that depends on how you're going to be moving about during the day! If you are.... - someone who lives somewhere with cold weather, but doesn't want to bundle up because you'll be inside once you reach your destination You should wear... - A silk base layer! If your office is well heated, you may need to remove it during the day, but it'll allow you to look oh-so-fashionable on your commute. If you are... - someone who bikes or runs to work You should wear... - light merino wool base, under waterproof mid layers, with more layers depending on how cold it is. Bonus is, since they don't smell, you can wear the same base layer for a longer period of time. If you are... - going skiing! You should wear... - heavy merino wool base. you won't get wet, but you'll also be warm while staying still. layer up on top of that! If you are.... - shocked at the cost of merino wool You should wear... - synthetic! It might smell, but it's cheap. Get it from army surplus or Uniqlo. You'll be warm outside, but hot the second you get inside. If you buy a slightly pricier brand, you'll be able to avoid a bit of that. Good luck!!