HTS power cable systems are an emerging technology aimed at competing with XLPE cable systems. Knowledge on the thermal operating conditions of HTS power devices is needed to estimate their availability when connected to a power system, because the HTS material must remain below its critical temperature to transport current. In this work, a simple finite difference method is used to assess the temperature distribution at certain cross-section of a second-generation coaxial HTS cable. This method has been implemented in MATLAB and its proper functioning has been verified with the software package FLUX. This method is a tool to establish temperature distributions among HTS cable layers under normal operating conditions. Additionally, the aim of this work is to serve as basis for future simulations including heat generation changes within the cable layers typically caused by grid fault events.