I usually wear a medium, but based on the reviews I ordered a large because in the spring and fall I'll wear a fleece underneath. I'm glad I did -- It's a perfect fit over the fleece, and it still looks like a good fit without the fleece. I also love the oversize hood, which should protect my glasses from the rain, and the long sleeves that actually come down past my wrists (I have long arms, and that's a problem sometimes). On top of everything else, the jacket is really cute -- I got the red hibiscus. I haven't actually had a chance to wear it yet because it won't stop snowing, but it seems like it will keep me dry.