I was looking for something lightweight for fall/spring type wear and this jacket looked like the nicest I could find.....the exact style I was looking for. It was then just a matter of what size to order.....I went ahead and ordered my usual XL in jackets since I'm 6' 205ilbs, size 35 waist, and have broad shoulders. The jacket was actually much better quality than I expected, but a little thicker than I had hoped.....but should work for the cooler SoCal evenings, spring and fall weather.....perhaps not warm enough for the winter months. The XL was just a bit big....not that it looked bad....just that it would definitely work if I was planning layers underneath. If I were to just wear a simple t-shirt, which I had planned to do, then a size L probably would do the trick. I will  be keeping the XL for travels to cooler places that require layers, and will order another in a size L for California wear and see how that works for me.