Outdoor thermal comfort assessment in outdoor and semi-outdoor spaces in tropical Malaysia – A case study of Universiti Malaya campus

Tropical urban environments in Malaysia expose dwellers to persistent thermal stress as high humidity and ambient heat exacerbate physiological strain and discomfort. This research investigates the impact of microclimatic variations across diverse spatial configurations at the Universiti Malaya on students’ subjective thermal perception relative to the physiological equivalent temperature (PET) index. The campus setting offers a rhythmic and predictable daily routine among the student population, establishing a stable behavioural framework for long-term habit thermal analysis. The study integrated microclimatic simulations and questionnaire surveys across four outdoor and semi-outdoor spaces that were distinguished by varying shading levels, spatial functions, and stay durations. Empirical results reaffirm the influence of mean radiant temperature in driving thermal discomfort, and demonstrate that effective shading not only minimizes objective PET values, but also improves the subjective perception of coolness among acclimatized users. Results suggest that residents accustomed to tropical climates may tolerate a broader temperature range than PET-based predictions imply. Long-term site familiarity and activity-based stay patterns foster thermal expectations and psychological adaptations that govern subjective thermal tolerance. Accordingly, the study suggests design recommendations that help to bridge microclimate modulation and human thermal experience to enhance liveability in the built environment.