Outdoor Thermal Comfort of University Students and Space Design Strategies for Alleviation: A Case Study in Xi’an

Amid rapid urbanization and the expansion of higher education campuses, the physical and psychological well-being of college students has garnered increasing scientific attention. Although outdoor activities are crucial for student health, participation rates are heavily constrained by outdoor thermal comfort (OTC). This study investigates the OTC of university students in Xi’an, China, utilizing the Universal Thermal Climate Index (UTCI) to assess thermal perceptions across four distinct open spaces and to propose localized bioclimatic design interventions. The results reveal four key findings: (1) The meteorological correlates of thermal sensation vary significantly by spatial typology; relative humidity (RH) and air temperature (Ta) dominate in sunken spaces (HB), whereas solar radiation (G), globe temperature (Tg), and wind velocity (Va) are the primary correlates in sports squares (CS) and activity squares (SH). (2) Thermal benchmarks exhibit remarkable spatial heterogeneity during summer. The Neutral UTCI (NUTCI) varied widely from 17.11 °C in hard-paved squares (SH) to 26.13 °C in shaded bridge areas (JG), with the corresponding neutral zones (NUTCIR) shifting accordingly. (3) Significant variations in thermal adaptation exist even within identical macro-climates, underscoring the necessity of microclimate-specific design. (4) Targeted bioclimatic strategies—including optimized vegetation deployment, shading structures, localized sprinkler systems, and permeable paving—are proposed. These findings provide actionable guidelines for urban planners and landscape architects to optimize campus environments, thereby encouraging outdoor engagement and enhancing student well-being.