Abstract
Rapid urban expansion in Katsina Metropolis has significantly altered land use and land cover, raising surface temperatures and giving rise to the Urban Heat Island (UHI) phenomenon in this semi-arid Sahelian setting. This study aimed to map and examine Urban Heat Island patterns across Katsina Metropolis using remote sensing and Geographic Information Systems (GIS) and to recommend practical mitigation strategies. Landsat 8/9 and Sentinel satellite images covering the dry-season months of 2016, 2020, and 2024 were processed using ArcMap and Google Earth Engine. Land use and land cover (LULC) classes were identified through supervised classification with a Random Forest algorithm, while Land Surface Temperature (LST) was retrieved from thermal bands after applying NDVI-based emissivity correction. Results reveal a clear transition from a strong Urban Cool Island (UCI) effect in 2016, where urban core temperatures ranged between 29–35 °C against rural peaks of 45–48 °C, to a pronounced Urban Heat Island by 2024, with urban surfaces registering 39–42 °C equal to or exceeding surrounding rural areas. Built-up area grew by approximately 8.4 km² between 2016 and 2024, while intra-urban green spaces were severely reduced and fragmented. The study concludes that UHI development in Katsina is primarily driven by rapid population growth, uncontrolled horizontal sprawl, widespread loss of urban vegetation and the replacement of traditional high-reflectance building materials with heat-absorbing alternatives. The research recommends incorporating thermal mapping into urban planning, protecting green infrastructure and expanding green corridors in identified hotspot zones and promoting the use of cool and reflective building materials.

Key words: Urban Heat Island; Remote Sensing; GIS; Land Surface Temperature; Land Use/Land Cover; Semi-arid city; Katsina