so cold (that) you could hang meat (in it/there)
Of a room, building, etc., having an extremely cold temperature, such that you could store raw cuts of meat without them spoiling. This B&B was terrible! The beds weren't made up properly, the bathroom was disgusting, and the room was so cold you could hang meat in it! Brr! That classroom is so cold that you could hang meat in there.
so cold you could hang meat
Fig. very cold; as cold as a meat storage locker. Lord it was cold there! So cold you could hang meat. A: How cold was it? B: so cold you could hang meat.