North East Cairo City (NECC), a relatively nascent urban area in Egypt, has experienced rapid expansion over recent decades. Understanding the environmental repercussions of land cover transformations in such regions has become increasingly paramount. This study investigates the intricate relationships between land cover change, NDBI, NDVI, and LST in NECC over twenty years (2000–2020) time span. We are employing a temporal series of Landsat imagery, including ETM+ and OLI/TIRS data, and sophisticated geospatial methodologies. The satellite imagery is classified into five distinct land cover categories: urban areas, bare land, agricultural areas, salinized soil, and water bodies. The findings indicate a significant increase in urban/built-up areas by approximately 211.2 km², accompanied by a concomitant decrease in bare land and agricultural areas by 196.2 km² and 23.9 km², respectively. Notably, the highest LST values were observed in bare land areas, escalating from 38–45°C in 2000 to 61–62°C in 2020, and in urban areas, rising from 36–37°C in 2000 to 60°C in 2020. The research revealed a pronounced correlation between the increase in built-up areas and the observed changes in LST, NDBI, and NDVI. Specifically, both NDBI and LST values exhibited an upward trend corresponding with the expansion of built-up areas. These results underscore the profound impact of urbanization on LST, offering critical insights into the consequential shifts in environmental indices. Furthermore, this study provides valuable guidance for sustainable urban planning practices in NECC, emphasizing the need for strategic interventions to mitigate the adverse effects of rapid urban expansion on the local climate and ecosystem.