(1) Background: This article presents a study that aims to provide a precise understanding of the temperature distribution within a Whole-Body Cryostimulation (WBC) chamber, whether it is empty or occupied by one or several individuals.; (2) Methods: The study employs a mixed numerical and experimental approach, utilizing simplified Computational Fluid Dynamics (CFD) simulations and an experimental analysis that employs thermocouples to determine the 3D thermal field in actual conditions.; (3) Results: The results reveal a non-negligible temperature difference between the setpoint and actual temperature in the middle of the cryochamber. Furthermore, it is shown that the presence of individuals inside the chamber results in both an average temperature rise and a more heterogeneous thermal behavior, which appear to be associated with the number of individuals present.; (4) Conclusions: The findings of this study emphasize the need for further research to establish temperature guidelines and standardize measurement methods for effective WBC treatment.