FACTORS AFFECTING OUTDOOR THERMAL COMFORT IN HISTORICAL PRECINCTS: A SYNTHESIS OF MICROCLIMATE, MORPHOLOGY, AND HUMAN DIMENSIONS

Abstract

Outdoor thermal comfort in historical precincts is shaped by a coupled relationship between climate, urban form, surface materials, vegetation, human characteristics, behavior, and heritage management. Unlike contemporary public spaces, historic precincts often contain fixed geometries, massive masonry, exposed courtyards, irregular streets, archaeological remains, mature vegetation, and conservation restrictions. These conditions can create shade and thermal buffering, but can also increase radiant heat exposure, restrict airflow, and limit the use of conventional mitigation measures. This paper reviews the literature on the principal factors that affects outdoor thermal comfort in historic streets, courtyards, plazas, archaeological parks, monuments, and heritage-tourism environments. The review organizes the evidence into six interacting domains: macroclimate and seasonality; local microclimate; morphology and spatial enclosure; materials and surface properties; vegetation, water, and shade; and human, psychological, social, and cultural dimensions. It also examines thermal comfort indices, field measurement methods, modeling approaches, and heritage-sensitive adaptation strategies. Across the literature, mean radiant temperature, solar exposure, shade availability, sky-view factor, wind, surface temperature, and adaptive opportunity emerge as particularly influential variables. Thermal comfort cannot therefore be represented adequately by air temperature or a single universal comfort threshold. The review proposes an integrated framework in which thermal exposure, spatial form, visitor perception, adaptive capacity, and conservation sensitivity are assessed together. Reversible shading, carefully managed vegetation, route and time management, and locally validated simulation are identified as promising approaches for improving visitor comfort while protecting historic character and fabric.