An apparatus for use with an intra-body probe, a distal end of which includes an ablation electrode and a temperature sensor, is described. While (i) the ablation electrode is driving an ablating current into tissue of a subject, and (ii) fluid is passed from the distal end of the intra-body probe at a fluid-flow rate, a processor receives a temperature sensed by the temperature sensor. The processor estimates a temperature of the tissue, based at least on the sensed temperature and at least one parameter selected from the group consisting of: the fluid-flow rate, and a parameter of the ablating current. The processor generates an output in response to the estimated temperature. Other embodiments are also described.
