I live in Texas and the summers here get really hot so I'm always on the lookout for cute and lightweight dresses.  This one fits the bill. :)  Like others have noted, the material is a bit thin but not so much so (in my opinion) that it is a problem.  I'm 5'5", 34D and approx. 145lbs.  I ordered a medium and it fits great (and believe it will still fit great when I shed another 10lbs).  It is pretty casual, but paired with a cute cardigan or shrug I could easily get away with wearing it to work.