Cities have faced rapid urbanization, which has changed the impact of the micro-thermal environment on residents' thermal comfort level. Therefore, planners need to understand the city's physical environment so they can identify and ameliorate the effects of the changing in micro-thermal environment. Researchers also need to identify and understand pedestrians' thermal comfort level in street canyons to determine which urban physical factors planners need to improve. This study aimed to observe how thermal comfort affects pedestrian behavior in micro-thermal environments and to determine which urban geometry factors influence pedestrians' thermal comfort. This study collected data in downtown Austin, TX using a mobile weather station, and analyzed the microclimate conditions experienced by pedestrians. A camera mounted on the weather station also allowed us to observe pedestrian behavior patterns. The results revealed that pedestrians tended to choose walking, sitting, and standing locations with high thermal comfort levels such as in the shade on the sidewalk. There was also some correlation between thermal comfort levels and pedestrian behavior patterns. The sky view factor (SVF) and tree canopy coverage ratio (TCR) were also correlated with pedestrians' thermal comfort. This study highlights the need for future research to develop a data collection method for efficient microscopic thermal environment research and a thermal environment estimation and analysis approach from a three-dimensional perspective. Display omitted •This study analyzed the relationship between pedestrians' thermal comfort levels and their walking, sitting, and standing behavior patterns.•This study analyzed the effect of urban geometry on outdoor thermal environments.•Developing a micro-scale thermal environment estimation model from a 3-D perspective is needed.•Further research on microclimate data collection and pedestrian observation methods is needed