Recent numerical experiments indicate that the fractional cloud coverage and relative humidity decrease with increasing temperature even though the evaporation and hence the condensation increases. In order to understand why this occurs, an analysis is made of the relative humidity equation in a simple wave model involving an eddy relative humidity wave interacting with a linear eddy vertical velocity wave. Also included are terms for zonal mean vertical velocity, radiative and sensible heating, and surface evaporation. The analysis is then extended to include mean zonal advection of relative humidity. It is found that for an increasing vertical velocity and static stability, the fractional cloud cover and relative humidity tend toward limiting values of 50%. Since the condensation is proportional to the vertical velocity and static stability, it increases. It is also found that horizontal advection decreases the fractional cloud cover and precipitation, and increases the relative humidity. The relative changes in these dynamical components help to determine the climatic sensitivity to temperature of the atmospheric hydrologic cycle. Moreover, because of the common dependencies of the various hydrologic components on these dynamical components, simple interrelationships among the fractional cloud coverage, relative humidity, evaporation and condensation can be derived.