The objective of the study is to develop a finite element model (FEM) of postmortem hyperthermia in the absence of internal and external heat sources and to clarify the conditions necessary for the occurrence of this phenomenon. ELCUT 6.5 software was used. We have developed a two-dimensional FEM of the postmortem temperature field of the head under convective heat exchange with the ambient air, taking into account the intensity of convective heat transfer and thermophysical parameters of anatomical layers of this body area. The possibility of postmortem heating of the surface and subsurface tissues of the corpse in the absence of internal and external heat sources was demonstrated. It was found that the occurrence of postmortem hyperthermia requires cooling the cadaver under low convective heat transfer with a small initial temperature gradient between the body surface and the ambient environment. It is recommended to take into account the possibility of postmortem hyperthermia and the conditions necessary for it in forensic medical practice when determining the time of death (TOD).