Urban Heat Island and its Impacts on Microclimate in Riyadh, Saudi Arabia

Abstract

Urban heat islands (UHIs) are emerging as a pressing environmental concern and the problem is exacerbated by rapid urbanisation, infrastructure expansion and land use changes, particularly in arid cities like Riyadh. Riyadh’s arid climate means that it is particularly susceptible to UHIs. The current research examines UHIs’ temporal and spatial dynamics, as well as how they affect microclimates in urban settings with the use of in-situ observations and remotely collected data. More specifically, measurements of dew point, humidity and temperature taken in the field in various urban typologies between December 2024 and February 2025 were examined along with Modis Land Surface Temperature (LST) data for the period 2002-2025. This revealed that LSTs and air temperatures were highest in densely populated regions and the city centre, while geospatial analysis indicated sizeable temperature differences between urban and non-urban areas. These findings were confirmed by the field data, revealing distinct microclimates which differed depending on land use and the time of day. The results lend weight to the belief that urban development is associated with higher temperatures, thereby suggesting that thermal behaviour is influenced by land use/land cover (LULC). As such thermal comfort can be achieved and the adverse effects of UHIs can be mitigated by designing urban spaces in an equitable way, utilising reflective surfaces, and incorporating green infrastructure, all of which have practical implications for environmental policy and urban planning.