I bought this before going on a trip to Sequoia National Park in fall and it was great against rain and wind. I usually wear a medium or a small and I am sure the medium would fit just fine, but since I wanted to wear a sweater or sweatshirt underneath I bought a large and it was just perfect. The sleeves were a littler long for me (I'm only 5' 3) but the adjustable velcro worked great to hold them in place. All in all a good jacket for a good price.