Fevers are an ancient feature of the inflammatory microenvironment. While fevers may improve the immune response to pathogens, mechanisms are unclear. We explore recent studies of how fever-range temperatures inform mammalian T cell metabolism, differentiation, and stress responses. Recent evidence indicates that metabolic programs initiated by fever are maintained upon return to thermo-normality, potentially providing a lasting benefit. Despite its impact, temperature remains overlooked and warrants further study. This is especially apparent when considering the wide temperature differential between tissues within the body and during inflammatory disease progression. We propose that differences in the metabolic and stress responses between T cell subsets upon thermal stress contribute to determining immune cell makeup and fate during inflammation.