The thermal environment is an important factor affecting human behavior, and the response of visitors to thermal conditions can be used in the effective design of open spaces. This study aimed to explore the relationship between the spatial-temporal distribution of visitors and thermal conditions in hot summer and cold winter regions. ENVI-met was used to reproduce the actual thermal environment, and visualization was achieved by ArcGIS. The number of visitor locations was recorded with their demographics, including gender (male and female) and age group (the elderly, adult and child), coupled with the simulated physiological equivalent temperature (PET) were investigated for six local solar times (LSTs) and open spaces in Chongqing, China. The results indicate that: (1) The neutral PET was 28.45℃ with a comfort range of 23.38∼33.52℃ in Chongqing. (2) The distribution of visitors was significantly affected by PET during the daytime (R2=0.89) and the effect was quite different during various LSTs. The exponential correlation was weaker when the PET was higher, with a narrow range (at 14:00 LST). (3) Thermal conditions can greatly affect the distribution of visitors in spaces providing visitors with long stay and high intensity activities. (4) The distributions of females (R2=0.76) and the elderly (R2=0.65) were more sensitive to thermal changes than were males and other groups. These results should help landscape designers to better understand the relationship between the thermal environment and the behavior of visitors and provide reference for efficiently adaptive designs in urban parks.