Wear of ceramics under dry sliding conditions is often governed by frictional heating. In this paper, a method is presented to predict the boundary between the mild wear regime and the severe wear regime due to frictional heating, and to a lesser extent, the prediction of the wear rate. To obtain this, the work of Bos was used to calculate contact temperatures. This model is essentially a fit, based on numerical calculations, making it possible to include heat partitioning between dissimilar materials while retaining closed form expressions. The stress resulting from the contact temperature can be compared with material properties to obtain the thermal severity of a contact. A dimensionless thermal severity number, TS, is introduced to determine the thermal severity of a contact. The model has been experimentally justified using alumina pin on zirconia disc measurements.