Urban sprawl is seen as a huge global challenge that primarily affects emerging countries with large populations. The outcomes of unplanned city growth into adjacent rural areas are uncontrolled wiping of natural resources and creating fluctuations in land surface temperature. This, in turn, influences climate change by causing heatwaves, droughts, and other extreme weather events. The present study uses spatial analytic techniques of RS and GIS to assess the urban sprawl in Ernakulam District of Kerala, India. Determining the Land Use/Land Cover (LULC), Built-up Index (NDBI), Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (LST) help to better understand how built-up areas and vegetation impact the surface temperature. Observations using Landsat 8 images from 2014 and 2020 showed that built-up areas have expanded by 2%, while waterbodies/wetlands have decreased by 1%. During the same period maximum, LST climbed from 34.3 °C in 2014 to 43.16 °C in 2020. Without proper urban planning, increasing surface temperature coupled with unchecked urban growth will harm the environment and quality of life. Hence an effective urban growth plan is required to limit urban sprawl.