Extreme climate events and global warming significantly affect energy retrofit planning, underscoring the need to consider future climate scenarios. This study evaluates the effectiveness of natural ventilation as a passive cooling strategy for a low-thermal mass building in a hot-humid climate, considering current and future weather conditions throughout this century. Using energy and Computational Fluid Dynamics simulations validated with in-situ data, the research evaluates three natural ventilation strategies: full, cross, and stack ventilation. Results demonstrate that natural ventilation reduces indoor air temperature compared to non-ventilated scenarios but faces challenges in maintaining indoor comfort levels during extreme external temperatures and under future climate scenarios. Full ventilation is most effective during cooler periods, while cross ventilation significantly enhances airflow across spaces. Stack ventilation shows potential in expelling hot air through vertical shafts, but its effectiveness is challenged during extreme heat events. These findings underscore the need for adaptive retrofit solutions, such as leveraging existing systems, implementing operational changes, and integrating shading devices to mitigate heat gain. Additionally, the study emphasizes the importance of combining passive strategies with mechanical systems to enhance energy efficiency and occupant comfort in historic buildings while addressing the anticipated impacts of climate change.