Informal settlements often referred to as ‘slums’ are a growing and pressing area of concern in the contemporary world. In South Africa, the population of ‘slums’ today consists of approximately eight million people, a number which has been on the rise since the national census in 1996. Due to the lack of recognition of ‘slums’ as legitimately occupied land, these informal urban spaces are characterised by a lack of service provision and a makeshift built environment. Therefore, vulnerability of residents inside these areas to environmental stresses is high, as shown by studies in informal settlements elsewhere in the world where there is corresponding weather extremes and displaced mortality. There is knowledge of the impact of increasing maximum temperatures and displaced rate of mortality, particularly within vulnerable members of the population. In a time of changing climate, where one of the more confident predictions for Cape Town, South Africa is that of increasing maximum temperatures, this vulnerability within ‘slums’ raises reasonable concern and need for timely adaptation. Vulnerability to weather extremes within informal settlements has resulted in autonomous adaptation approaches being adopted by residents. The nature of adaptation adopted inside ‘slums’ is found to be distinct from formal definitions of adaptation due to the unique circumstances of low resource availability within settlements.