Answer:
"Zero at the Bone" means ""cold" as in "It's zero at the bone in here." A more common slang phrase that is closely related is: "Cold to the Bone," which is used to describe one's feelings of being cold, as in, "I'm "cold to the bone" (I am so cold that my bones ache with the cold, the cold having penetrated my body progressively deeper and deeper, I am almost cold clear through). Another idiom that is used in similar situations as "Zero at the Bone" is: "You could hang meat in here." (A phrase which evokes a picture of a packing house with rows of hooks with animal carcasses hanging on them.) (If one wishes to be humerous, the phrase: "You could hang meat in here." is used in situations where such an image (of carcasses hanging) is most out of place: at a wedding (or worse, a funeral!) in a beautiful chapel, for instance.