Changes in body temperature influence our immune system. While increased temperatures (e.g. during fever) can have stimulating effects, anti-inflammatory treatments induce low temperatures to supress the immune response. Although this is well-established in medical treatments, details on the cellular or molecular mechanisms of thermic immuno-modulation remain elusive. To investigate how temperature affects early T cell signalling, we studied primary murine CD4+ T cells. For precise temperature control, we functionalized supported lipid bilayers (SLBs) on microscopy-compatible, heatable glass substrates (VAHEAT, Interherence). Mimicking the surface of antigen presenting cells, the SLBs provide cognate antigen, costimulatory and adhesion proteins which induce specific T cell activation. Via ratiometric calcium imaging, we compare T cell behaviour in hypo-, normo- and hyperthermic conditions, revealing temperature effects on cell migration, antigen recognition and Ca2+ levels within cells. Additionally, we show how elevated temperatures damage protein-functionalized SLBs and present strategies to protect SLB integrity.