We illustrate how the Hawking Hubble temperature could simply be the minimum tem- perature above zero anywhere in the Hubble sphere. It perhaps defines the “temperature gap,” so to speak – the minimum temperature above zero – and therefore, also the “energy gap.” Of course, this does not exclude that Hawking radiation from any black hole of any size may also occur. Secondly, the Planck temperature is likely the maximum temperature at any localized subatomic point in the Hubble sphere. Additionally, we demonstrate how the Cosmic Microwave Background (CMB) temperature could simply be a form of geometric mean temperature between these minimum and maximum temperatures over the course of cosmic time. This mathematical discovery suggests a re-consideration of Rh = ct cosmological models, including black hole cosmological models, even if it possibly could also be consistent with the Λ-CDM model. Most importantly, this paper contributes to the growing literature in recent years asserting a tightly-constrained relationship between the CMB temperature and the Hubble constant, as well as other global parameters of the Hubble sphere.