Variation in Land Surface Temperature in Informal Settlements Relative to Surrounding Heterogeneous Areas: Insights from Dunoon and Masiphumelele, Cape Town

Informal settlements are home to more than one billion people worldwide, with forecasts suggesting this number may increase to nearly three billion by 2050. Although informal settlements constitute a significant component of urbanization in the Global South, they are unsafe and unhealthy places to live, as residents are exposed to various environmental challenges, including increasing temperatures. However, relative to other climate-related hazards, heat stress in informal settlements is under-researched. This paper, therefore, aims to analyze land surface temperatures (LSTs) in informal settlements relative to those in surrounding areas. Focusing on the study areas of Masiphumelele and Dunoon in Cape Town, South Africa, the study utilized downscaled 10 m resolution satellite imagery from 2020 to 2025. The LST was derived from Landsat 8 Collection 2 Level 2 Surface Reflectance and Surface Temperature products. Four indices were also generated to further analyze the spatial distribution of LSTs: the normalized difference vegetation index, the normalized difference built-up index, the bare soil index, and the normalized difference water index. Showing that heat intensity in informal settlements is a relative phenomenon influenced by many factors, Dunoon had a lower mean LST than the surroundings, while Masiphumelele demonstrated elevated mean LST relative to the surroundings. The study provides empirical evidence of heat-related patterns to inform planning and climate adaptation strategies in informal settlements, including the equitable provision of green and blue infrastructure.