The Urban Heat Island (UHI) phenomenon is a prevalent environmental issue in urban landscapes, impacting both climatic and ecological processes. This study examines the spatiotemporal patterns of Land Surface Temperature (LST) to analyze the magnitude and characteristics of the UHI effect in Herat, a major metropolitan city in Afghanistan. The seasonal LST and UHI patterns have been correlated to the land use/land cover (LULC) changes that occurred in this city over a decade (winter and summer; 2008–2009 and 2018–2019). The results indicated that the city experienced rapid expansion during the study period. Barren land and vegetation were the main classes that got converted to the built-up class. The study of LULC changes showed that the built-up area has expanded by 61.7% in Herat. The UHI phenomenon was found to be dominant in the summer season. The maximum UHI intensity (UHII) was noted at the city center due to the dense urbanization and high anthropogenic activities. The maximum average seasonal UHI intensity of Herat was observed to be 1.6 °C. The present study is expected to help city planners in framing sustainable land management policies.