<p>Informal settlements represent cost-effective solutions to providing access to urban economies for the poor, but these come at steep long-term costs. While the growth and efficiencies of informal settlements are noteworthy, these settlements contribute to the vulnerability of our cities due to their limited infrastructure investment, poor construction practices and material choices, location in highly exposed climate change hazard areas, and chronic resource constraints. Representing typical informal settlements in Southern Africa, this article discusses the sensitivity, exposure, and limited climate response capacity of the Melusi informal settlement located in Tshwane, South Africa. It highlights the constraints of self-built autonomous development and ultimately calls for in situ upgrade initiatives and policies that appropriately and timeously include built environment professionals to address these concerns. The research followed a mixed methods approach to document the impacts and exposure to excessive heat and precipitation-driven flooding. The findings highlight the cumulative risk levels and elevated exposure of informal settlements to adverse climate effects, even during climate-induced hazards that were negligible in magnitude. This article contributes to climate change-responsive urbanism by highlighting informal settlements’ ingrained vulnerabilities, exposures and the response measures needed to address it.</p>