very warm, and they squeak when I walk.  I let them slip off when I sit down, or else my feet will get sweaty, which can also make the lining pull out when you take your feet out.  Still, the fleece has held up well for the past couple months, and of course crocs are comfortable.  The lining is removable and washable, which will be good if they ever start to smell (though I am not expecting them to get stinky or anything).  If the lining ever wears out, I will just wear them with socks.