This chapter provides an overview of how low-onset (e.g. temperature rise) and rapid weather events (e.g. floods and heavy rain) affect the spread of vector-borne (such as malaria, dengue) and water-borne (such as typhoid, cholera) diseases. In particular, it examines the nature of these impacts on the urban poor living in low-income settlements in Dar es Salaam, Tanzania, addressing the glaring knowledge gap on health, climate change and urban poverty.