As others have pointed out, these pants are lightweight--not fleece lined.  The material is thin, but not too thin, and turned out to be just perfect for me.  I was looking for something to wear during therapy sessions after knee surgery, and  I have been pleased with the roomy legs, the comfortable fit, and the fact that the pants do not feel heavy or bulky.

A word about sizing, however.  I ordered Large , and at first sight I thought they would be much TOO large.  However, after they were washed they seemed to shrink a bit into a perfect fit--what I would call a "roomy medium".

For the price and for my needs, these pants have been a great purchase.