The cooling effects of green infrastructure compared to blue infrastructure in urban areas are well explored in the existing literature. However, the effect of urban blue infrastructure on the surface temperature of urban areas is less explored. Therefore, this study aims to investigate the extent of cooling effects provided by water bodies on the nearby built-up areas. The five largest water bodies in Varanasi, India, were selected to assess the cooling influence on Local Climate Zones (LCZs) within a 200-m radius around the water bodies. The Land Surface Temperature (LST) maps were prepared using geoinformatics. Buffer zone analysis was used to calculate cooling factors, including cooling indices and LCZ indicators. The results exhibited that the average LST of the water bodies and surrounding LCZs increased significantly from 2014 to 2024, with a peak of 43.53 ℃ in June 2024 and a low of 29.78 ℃ in April 2014. Built-feature LCZs (3 and 6) exhibited higher and concentrated LST values, while LCZ 9 showed scattered patterns. The LST variation curve near water bodies revealed an initial increase before stabilizing, indicating their cooling effect. These findings will assist policymakers in preparing climate-sensitive urban planning for water bodies.