The integration of Phase Change Materials (PCMs) in building envelopes has gained significant attention in recent years as a promising solution for thermal energy storage. PCM technology utilizes the latent heat of a material to store and release large amounts of energy, making it an effective method for passive thermal regulation and stabilization of the indoor building temperatures. However, to fully exploit the potential of the PCM, it must be completely charged and discharged in each cycle. With this fact in mind, this work aims to assess the performance of the PCMs in Moroccan climate zones, as well as to find out the best combination of PCM and natural ventilation to enhance the overall cooling energy performance of buildings. To this end, a numerical investigation was conducted in a residential building located in six climate regions of Morocco. The EnergyPlus software with the integrated PCM hysteresis model was used. Firstly, the effect of the PCM phase change temperature throughout the year was evaluated considering six cities located in those climates. Subsequently, an analysis was conducted during the summer season, resulting in the identification of the optimal configuration regarding PCM phase change temperature and thickness for each city. Furthermore, various natural ventilation scenarios i.e. night and whole-day natural ventilation, were implemented to investigate their impact on the process of PCM charge–discharge cycle. The results reveal that the integration of natural ventilation in PCM-enhanced building was an effective method that solidifies the PCM every required cycle. The integration of PCM with night natural ventilation (NNV) leads to improve the PCM activation by between 22.4% and 26.1%, in the warm and temperate Mediterranean climate. However, whole-day natural ventilation controlled (NVC) further decreases cooling energy consumption by 2–9% compared to NNV in all studied climates, making it the best combination.