If you're talking bone chilling cold, wind, snow or freezing rain, dark skys and heavy dampness in the air... Carhartt is cotton and has no insulation value when wet and does not dry out easily. And cotton will soak and hold moisture. Fleece is very warm, breathes well, and dries quickly. However, it isn't the toughest material for exterior wear and soaks up water pretty quick when worn on the outside in wet conditions. In the past fleece didn't block wind very well either, though new tech wind barriers may have helped in that regard. I like fleece shirts and light sweaters for layering underneath a stronger outer garment. Fleece works fine in dry conditions and maybe light cover that won't snag it too much.
For the bad days, think Filson wool on the outside, with fleece undergarments, and polypro moisture wicking underwear against the skin. An inner sock with moisture wicking properties and SmartWool over the top as a second pair of socks will take good care of the feet. A Filson hat of the type with the buckle in front that will allow you to slide down flaps for ear protection, or, totally unbuckle it and drape the thing over the neck and shoulders for complete head/neck protection against wind, rain, snow, ect is great in foul weather. I like Filson wool, however, the Columbia Galletin Range stuff aren't terrible garments for the money. L.L. Bean has some decent wool. Cabela's wool whipcord pants are excellent. Cabela's also has some other decent wool garments. Wool is tough and wears like iron, blocks wind quite well when a tight weave is used, is naturally moisture resistant, and maintains insulation qualities even when soaking wet, and breathes fairly well. Downside? It can be heavy to wear. I think a heavy wool garment feels comforting when the weather is doing its best to ruin your hunt - or worse!