We study the correlations between Precipitable Water and Atmospheric Temperature using both satellite observations and the output from climate models. For large spatial averages over the tropical oceans, we find that the scaling between these variables that is predicted by climate models is in good agreement with that derived from the most recent versions of SSM/I precipitable water and MSU/AMSU-derived lower tropospheric temperate. The both the modeled and observed scaling is the same for seasonal, interannual, and decadal time scales. When reanalysis output from both ERA-40 and NCEP-50 is evaluated, the long-term scaling between precipitable water and temperature is found to be in disagreement with the observed and modeled scaling, suggesting problems with the precipitable water data in the reanalyses. We also investigate the spatial structure of the precipitable water/temperature correlations in observations and models, with an eventual goal of using the correlation structure to help evaluate model performance.