I don't think they would be warm enough for really cole weather. Think waterproof nice quality fabric lined with flannel, the fleece lining is not very thick.
Ed is probably 19 inches at the shoulder, his neck to tail measure was between 19 and 20 inches, and I didn't really measure his pot-belly (weighs 32 lbs). the medium was usable but came a couple of inches short on his back and only about 2/3 the way down his sides.The velcro 'belt' was plenty long enough, and the chest wrap was fine. Most of his other clothes are this size, or way too big.
I first thought the large way too big (there was quite a big difference) but on second look decided to keep it, Ed will be well covered. He is an in-between sized boy, hard to fit, good thing we live in Florida!