Abstarct: Climate change and the phenomenon of global warming have increasingly highlighted the importance of paying attention to the quality of outdoor environments and thermal comfort in urban open spaces. This issue is particularly critical in temperate and humid climates such as the coastal region of Fereydunkenar in Mazandaran Province, where appropriate thermal conditions directly influence citizens’ well-being, extend the duration of their presence in public spaces, enhance urban vitality, and ultimately contribute to the environmental and economic sustainability of neighborhoods. Within this frxamework, shading is recognized as the most effective passive design strategy. Among various shading options, tensile membrane structures have attracted considerable attention from designers and researchers in recent years due to their unique characteristics, including lightweight construction, the ability to span large areas, relatively rapid installation, cost-effectiveness, and the capacity to regulate light and thermal conditions. Despite this high potential, there remains a noticeable research gap regarding the quantitative and precise evaluation of the performance of these structures in improving thermal comfort indices within the specific climate of northern Iran. To address this need, the present study was designed and conducted through a combined approach in two main phases. The first phase, baxsed on a review–analytical research method and supported by library studies, focused on extracting and formulating the theoretical foundations related to membrane structures and thermal comfort assessment indices. The second phase, aimed at obtaining objective and measurable data, employed computer simulations using two specialized software programs: ENVI-met for microclimate modeling and ANSYS Fluent for detailed analysis of airflow and radiant fields.In this phase, the thermal performance of four membrane canopy scenarios—including two saddle-shaped forms with dimensions of 9×9 meters, with and without wind flow—was evaluated as case studies under the real climatic conditions of Fereydunkenar on the hottest day of the year. baxsed on the simulation results, the selected canopy was able to reduce the Mean Radiant Temperature (MRT) beneath it by approximately 12°C during peak solar radiation hours compared to the surrounding open environment. This significant temperature reduction, which leads to conditions within the thermal comfort range, clearly demonstrates the efficiency and high potential of tensile membrane canopies in moderating harsh climatic conditions and creating high-quality, sustainable urban open spaces in temperate and humid regions of the country. These findings can provide a reliable basis for decision-making by designers and urban planners in future projects.