As urbanization and the heat island effect intensify, comfortable and healthy outdoor micro-environments are particularly important for sustainable urban development, encouraging more outdoor activities. Fewer studies have focused on differences in thermal comfort and thermal physiology of users in potential outdoor open spaces. Therefore, this study aims to examine the differences in thermal comfort and thermal stress among users of common outdoor open shady spaces, contributing towards a better thermal experience and mitigating heat stress. In this study, a field investigation of corridors and greenways was conducted on a campus in Guangzhou in the summer based on subjective questionnaires and objective measurements of thermal environment, and thermal physiological parameters. The results found that people were more likely to experience good thermal comfort and weaker intensity of thermal stress in corridors with significant differences in physiological responses. Furthermore, the upper limit comfort temperatures of the corridor and greenway were 34.0 and 33.4 °C, respectively. In addition, it can be concluded that the corridor was a more optimal space for outdoor shade before evening, whereas the greenway was more optimal in the evening in summer. The findings determine the thermal benchmarks for typical outdoor shady spaces in hot and humid regions in summer, which can help designers create comfortable outdoor public spaces that improve thermal comfort and people's health.