The main motivation of the presented paper is to study the amplitude and location of the maximum temperature (T-max) and maximum temperature gradient (Delta T/Delta x(max)), respectively, as well as the performance parameters of the modeled, single, planar, anode supported, solid oxide fuel cell (SOFC) with internal methane steam reforming at different operating conditions (i.e. current density and inlet velocity of fuel gas). The reforming reaction and locally increased current density lead to inhomogeneous heat generation within the SOFC that results in inhomogeneous distribution of temperature. Due to the latter, a comprehensive, three-dimensional, thermo-fluid model of the SOFC has been developed and implemented in software package COMSOL Multiphysicse (R) 4.3. The simulation results show that the amplitude and location of the T-max and Delta T/Delta x(max) within the modeled SOFC depend on operating conditions. The data about their values can be efficiently used instead of temperature measurements with expensive embedded thermocouples when a realistic, operating SOFC is controlled. The results also show that the current density and the inlet velocity of fuel gas are the key parameters to improve the fuel utilization and the total conversion efficiency. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.