Climatic chambers are of great importance in research and development to conduct tests of components in closed environmentally controlled conditions. The growing demand from the industry to fulfill stricter international standards creates the necessity to ensure that the thermofluidic behavior of climatic chambers guarantees high-quality consistency in their interior domain. At present, scientific research on climatic chambers available in the literature is scarce and is mostly based on lumped modeling, hence not addressing the heterogeneities that arise in the interior of the chamber. In this work, an in-depth 3D model of the velocity and temperature fields that develops in the interior of climatic chambers was developed in computer fluid dynamics (CFD) and validated with the experimental data from a new prototype. The key objective of this research was to establish a validated framework for model-based design optimization of climatic chambers. The proposed model showed good agreement with the experimental data with a difference of 0.6 m/s and 9.65 °C in the velocity and temperature fields, respectively, thus validating its applicability to perform model-based design optimization of climatic chambers.