In recent years, urban heat island has become a critical issue especially in the tropics, thereby drawing attention of researchers. Urban heat island poses considerable influence upon the thermal performance of an open space in terms of its social interaction, environmental and therapeutic potentials. To provide benefits towards healthy urban living, proper planning of open spaces is seen to be crucial. In the tropics, the thermal performance of an open space can only be effectively achieved when determinant variables on site and the surroundings are not neglected. This paper provides a comprehensive review of previous studies on the effect of different determinant variables for open spaces with regards to thermal performance in the tropics. Determinant variables such as built forms and configurations, orientation, built envelope and layout, building fabric and surface materials, and natural features like vegetation and water features were reviewed and analysed to identify their influences toward the thermal comfort of open spaces and how the effective passive cooling potential could be enhanced. In conclusion, to achieve the best possible thermal performance for open spaces, determinant variables of greater influence such as built form and configuration, orientation and the built envelope and layout are stressed throughout the design planning.