Background: Rapid urbanization in Kuala Lumpur Metropolitan City (KLMC) has resulted in urban heat island (UHI) effect that deteriorated public health of the urban dwellers. In a motive of identifying the heat sources, this study reported the perceived warmness and the characteristics of Open Park Spaces (OPS) that induce the reported warmness of the surrounding environment in Kuala Lumpur Metropolitan City (KLMC), a tropical city of Malaysia.Methods: A cross sectional survey using structured questionnaires is conducted on randomly clustered respondents in selected localities of KLMC from January to May, 2018. Pearson correlation is performed to examine the relationship between perceived characteristics of OPS and perceived warmness of the surrounding environment according to three time slots of a day.Results: The outcomes demonstrated that respondents felt warm during nights (89%) compared to morning (75%) and afternoon (87%). Meanwhile, the existing OPS are reported to be equipped with a mix of biodiversity such as birds, rodents and insects (89%), a mix of natural plants and animal populations (88%), water bodies (88%), variety of plants (86%), well-maintained grass surfaces (80%), ornamental flowers (79%) as well as wooded pasture (78%) in their neighbourhood. As the maximum warming sensation is reported to be felt at nights, especially in the presence of water bodies (r= 0.318, p<0.01) and wooded pasture (r= 0.222, p<0.01) in the vicinity, the integration of heat ameliorators across the existing water bodies and wood pasture deemed essential to reduce the surrounding heat impacts.Conclusion: The findings of this preliminary investigation are useful for urban designers and policy makers to make tacit evidence-based decisions.