Dani and Phillip, I respect your opinions here and cannot argue with your observations. The danger is that we take an anthropomorphic view. We are warm-blooded and feel most comfortable when the ambient temperature (at our skin, so under any clothes) is close to body temp. Bees are cold blooded and so don't feel the cold the same way we do. They do have the ability to generate heat by exercising their wing muscles, but that is used in combination with the insulating properties of the bee cluster. The ambient temperature in the hive, outside the cluster is at ambient. That means that the insulation value of the hive is not relevant, as insulation only works if there is a temperature gradient across it.
According to Moeller 1978:
"At the outer periphery of the roughly spherical cluster occupying the interspaces of the combs, the bees are tightly packed to form an insulat ing band or shell. The outer edge of this cluster never falls below 43°F (6.11° C) (10) and is usually in the mid-50° (12-13°) range. If the body temperature of a bee falls to 42° (5.56°), it loses the power of motion and will drop. At 28.5° (1.94°) the body tissue freezes solid. Thus, to maintain life the temperature cannot go below 43° (6.11°). In the remainder of the hive space not occupied by bees, the tempera ture falls just as low as the outside. Colonies that build combs in such exposed places as on limbs of trees cannot withstand the cold, piercing winds of northern climates and will not survive. Thus, the main purpose for seeking the confines of a cavity seems to be wind protection."