Thermal comfort refers to psychological satisfaction with the thermal environment. Urban Heat Island (UHI) and global warming pose significant challenges to comfort levels. This study investigates the relationship between thermal comfort, occupant activity behaviour, climatic parameters, and psychological perceptions in Kanakakkunu Park, Trivandrum—a vital green space for diverse age groups, renowned as the city’s lungs. The study segmented the park into zones based on features like shading, paving materials, and tree density. Each zone underwent separate analysis to ensure precision. The research comprised two main sections: the first involved observational analysis and activity mapping to understand occupant behaviour non-intrusively. Thermal variations in each zone were recorded using thermal imaging. The second section conducted field measurements using TESTO 440 instruments to capture air temperature, humidity, and wind speed-the parameters influencing thermal comfort. Simultaneously, a quantitative survey gauged occupants’ perceptions. Thermal comfort indices, particularly the Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD), were evaluated using the PET scale. Results indicated that 50% of respondents prioritized thermal comfort in their choice of location, with some zones also valuing place quality. The study underscores thermal comfort as a primary determinant of occupant behaviour, while acknowledging the role of place quality. Future research should explore behavioural changes stemming from discomfort exposure.