Bangladesh's capital, Dhaka, is one of the world's most crowded and rapidly urbanizing megacities. Its thermal environment has changed dramatically over the last three decades due to uncontrolled growth and the conversion of aquatic and vegetative areas into built-up zones, which has exacerbated the Urban Heat Island (UHI) effect. The UHI effect in Dhaka is deeply connected with its long-term spatial dynamics in relation to changes in Land cover. This study examines urban heat island (UHI) patterns in Dhaka from 1990 to 2025 utilizing multi-temporal satellite-derived Land Surface Temperature (LST) data and Land use Land cover (LULC) classification. he intensity of UHI was classified into Very High, High, Moderate, Low, and Very Low categories, and spatial change detection was utilized.Statistical metrics, including mean and standard deviation, were computed to assess changes over time. Due to thick, impermeable, unplanned urbanization with little green space, South Dhaka, and especially Old Dhaka areas like Gendaria, Gulistan, Motijheel, and Chawkbazar, exhibit the highest UHI intensities, according to the results. On the other hand, because of their greater vegetation cover and lower levels of urbanization, North Dhaka neighborhoods like Uttarkhan and Dakshin Khan have low to very low UHI. According to LULC study, densely populated areas with little vegetation have the highest UHI values, while vegetation and water bodies have the lowest. Bare ground shows moderate to high intensity. Very High UHI zones grew almost 3 times and High zones by +59.48% between 1990 and 2025, whereas Low and Very Low zones decreased by −38.37% and −49.64%, respectively.Mean UHI shifted with stable standard deviation, reflecting spatial redistribution rather than uniform warming.These results demonstrate how land cover change has a significant impact on UHI dynamics and stress the necessity of climate-sensitive planning, the preservation of green and blue areas, and focused mitigation techniques to increase Dhaka's thermal resilience.