I'm a recent transplant from the oppressive heat of central Texas to the snowy mountains of SW Colorado. In other words, I get cold easily. I wear this as my base layer when snow-shoveling the drive or when snowshoeing for several hours when the temperate is above freezing but still cold. I work out hard and sweat a lot, yet these wick well and keep me dry and warm. The anti-microbial treatment really works on blocking the sweat odor too. I really love the malibu blue color, and the cut is cute and flattering. Plus I couldn't believe the price! I have been used to buying performance wear through REI, and am so pleased to have found this great product at at least half the price I would have paid. I have purchased several Hot Chillys products and am definitely a convert.