I bought this for winter road cycling and Nordic skiing. I am 5'10" 155 lbs. with 32" inseam. Size medium was appropriately sized for me. I tend to get cold easily, so bear this in mind when I say that on a 32 degree ride, I was cool, but not uncomfortably-so. I would not have wanted to go any colder without adding another layer, however. The design and construction of the tights is top notch. The windblocking fabric on the front panels is not breathable (no surprise there), so the fronts of your legs can get sweaty which is not ideal on a cold day. That said, I don't know how Pactimo could get around this issue and keep the water and wind resisting properties of the fabric. I wish they offered a version of this without the chamois, as I would prefer to wear shorts as a base layer for some added insulation, plus the chamois is not necessary for skiing. Overall, this is a very nice product and I don't think you will be disappointed with it.