This study presents a new heuristic approach that includes temperature in rock physics modelling. Temperature is the most important factor for chemical compaction, and hence velocity evolution in the chemical compaction domain. Given brine-saturated rocks, the modelling is dependent on only three input parameters: lithology (Vsh), porosity, and temperature. The simplicity of the approach, and the ability to model all stages of diagenesis in sands and shales, make this strategy suitable in early exploration settings where little information is available. Due to fundamental differences in sands and shales, one sand model and one shale model are proposed, both temperature-dependent. The models are calibrated to local sands and shales, and then used to predict scenarios not observed in the data set. It is further demonstrated how the models can be used to guide seismic interpretation when interpreting shale-sand reflections at different diagenetic stages. Finally, the suggested models are also used to predict expected AVO behavior during mechanical and chemical compaction.