Relatively large values of the temperature for the dust component of plasma systems are an area of concern in the understanding of such systems. Dust temperatures are regularly observed to be several orders of magnitude higher than the temperatures of the other plasma components, leading to questions of the validity of the measurements. In order to address such concerns, the phase space distribution was measured for a weakly coupled dusty plasma system. The measurements are used to illustrate the differences between two metrics of the thermal motion of the dust component, namely, the temperature and the thermal energy density. It is shown that, by considering the thermal energy density, instead of the temperature, the energy associated with the random motion of the dust component is comparable to that of the other plasma species.