Outdoor thermal comfort in residential neighborhoods plays a key role in enhancing the well-being of residents and pedestrians. This factor is heavily influenced by urban design features, particularly the form and shape of building blocks, which affect parameters like solar radiation, wind patterns, and air circulation, ultimately altering thermal comfort indices. This study investigates the impact of building block forms and edge shapes on outdoor thermal comfort in an urban neighborhood in Sabzevar. Three distinct block forms were generated through variations in the building’s volume, such as protrusions and recessions. Using the ENVI-met software Version 4.4.5, the climatic parameters and thermal comfort indices were evaluated. This software is one of the most widely used tools for simulating climatic conditions and thermal comfort in open spaces, which is a powerful tool for simulating microclimates and evaluating thermal comfort in open spaces. This software allows urban researchers and designers to examine the various effects of urban design, vegetation and environmental features on climatic conditions and thermal comfort. Comparing UTCI and PET indices, the results revealed that Block 2, with a central protruding volume and the separation of the courtyard into northern and southern sections, showed the highest thermal comfort levels. In the summer solstice, the UTCI and PET values were 38.90°C and 46.65°C, respectively, while in the winter solstice, they were -19.10°C and -4.02°C. Block 2 provided the closest thermal comfort to the acceptable range compared to the other forms. These findings offer valuable insights for architects and urban planners, who can optimize the design of residential blocks in similar climates to enhance outdoor thermal comfort.