In recent decades, rapid population growth and uncontrolled urban expansion have significantly altered urban form, reshaping city landscapes worldwide. These transformations, combined with ongoing climatic and environmental changes, have profoundly impacted citizens' quality of life and the sustainability of urban ecosystems. A key phenomenon in this regard is the formation of urban heat islands (UHIs), characterized by elevated surface and atmospheric temperatures in urban areas compared to surrounding rural regions. UHIs pose significant environmental challenges, including increased energy consumption, reduced air quality, and threats to the sustainable development of urban areas, particularly in vulnerable coastal regions. This study investigates the relationship between urban form and land surface temperature (LST) in the coastal cities of the Caspian Sea, a region experiencing rapid urbanization and environmental stress. We employed k-means clustering to identify distinct urban form patterns—compact, dispersed, and balanced—and analyze their thermal impacts. Remote sensing data from Landsat 8 satellites, collected for the years 2014 and 2024, were processed using Google Earth Engine to derive LST, classify land cover/land use, and compute landscape metrics. These metrics, analyzed in FRAGSTATS, provided insights into spatial patterns of urban development. The results revealed that compact urban forms, characterized by high patch density, connectivity, and aggregation, are associated with significantly higher LSTs, exacerbating UHI effects. In contrast, dispersed urban forms, with lower density and fragmentation, exhibited cooler surface temperatures. The clustering analysis confirmed a clear correlation between urban form and LST, highlighting the role of spatial configuration in thermal regulation. These findings emphasize the critical need for sustainable urban planning strategies that prioritize green spaces, urban ventilation, and balanced growth to mitigate UHI effects. By integrating such approaches, coastal cities can enhance environmental resilience and improve livability, addressing the challenges posed by urbanization and climate change.