The co-occurring trends of rising temperatures and population aging threaten to create “hotspots” of rapidly growing concentrations of older adults and increasing high-temperature extremes in several world regions (1,2). These combined stressors will place intense demands on local governments, healthcare systems, and service providers to develop infrastructures and response systems that meet older adults’ distinctive needs. However, hotspots in lower-income nations across the Global South may lack the resources and institutional capacity to respond effectively (3), while hotspots in historically Republican-leaning U.S. states like Texas and Oklahoma currently lack climate action plans that could protect large and growing populations of older adults (4,5). In this editorial, we describe the outsized impacts of extreme heat on older adults’ well-being, document how the geographic patterning of population aging and rising temperatures places particular regions at risk, and urge tailored preventative efforts and adaptations to protect older adults.