For sizing, I usually wear a large tall, I'm 6'-0" and around 220, a large tall fits me perfectly, but in this case I went with a large and it fits me well, tight, but well, the sleeves run up a bit when stretching to reach for something, but not too bad. I live in Minnesota, we get some cold days combined with strong winds, right after this jacket arrived we had an arctic blast come through, -10 F temperatures and -30 F wind chills, with this jacket, some gloves, and a hat, I was completely comfortable. This jacket lets in no wind at all, its waterproof with the Omni-Tech and warm with the Omni-Heat. I went through a lot of jackets before sticking with this one, while expensive, its really 3 jackets in one. It is plenty warm with the liner, will make a great rain jacket with the liner out, or just the liner for when its around 30.