We demonstrate that materials with comparable thermal dependence of coercivity under normal laboratory measurement conditions, differing only in sign, have quite different properties at recording frequencies. Barium ferrites, with positive dHc/dT, have augmented thermal dependence, while oxides, with negative dHc/dT, exhibit weaker thermal dependence at recording frequencies. Experimental data and theoretical analysis confirm this behavior. Two methods of predicting coercivity as a function of temperature, for recording time scales, are presented. The implications for direct overwrite performance while thermally cycling are discussed.