People　spend　most　of　their　time　indoors.　However,　indoor　temperature　and　individual　thermal　exposure　are　generally　not　considered　in　epidemiological　studies　of　temperature　and　health.　Based　on　the　American　Society　of　Heating,　Refrigerating,　and　Air-Conditioning　Engineers　(ASHRAE)　RP-884　Database,　the　ASHRAE　Global　Thermal　Comfort　Database　II　and　the　Chinese　Thermal　Comfort　Database,　this　study　first　explored　the　relationship　between　outdoor　temperature,　indoor　temperature　and　thermal　sensation　from　a　global　perspective.　Moreover,　the　potential　influence　of　spatiotemporal　heterogeneity　on　health　studies　was　explored.　A　breakpoint　was　found　at　approximately　11.5　degrees　C　in　the　segmented　regression　of　indoor　and　outdoor　temperature,　and　the　slope　of　the　curve　was　greater　when　outdoor　temperature　was　above　the　breakpoint　(n　=　67,896).　Based　on　multi-group　propensity　score　matching　(PSM)　and　generalized　additive　models　(GAM),　spatiotemporal　heterogeneity　was　found　in　the　relationship　between　indoor　and　outdoor　temperatures　after　adjusting　for　building　type　and　year.　Furthermore,　the　relationship　between　indoor　temperature　and　thermal　sensation　was　influenced　by　the　outdoor　temperature.　This　study　highlights　the　importance　of　considering　indoor　temperature　or　individual　thermal　exposure　in　temperature-related　health　studies.