Abstract Thermal sensitivity represents the magnitude of water temperature association to changes in air temperature (AT), yet global patterns in the responsiveness of lake surface water temperature (LSWT) to atmospheric warming at different temporal scales remain poorly characterized. Using LSWTs from 35,263 lakes worldwide, we quantify the spatiotemporal variability in LSWT sensitivity to both long‐term atmospheric warming and short‐term extremes. On average, LSWTs respond at 76% to the rate of long‐term atmospheric warming (∼0.76°C LSWT change per 1°C change in AT). The sensitivity of lake heatwave frequency, duration, and cumulative intensity to corresponding atmospheric heatwave metrics is 55%, 84%, and 59%, respectively. These sensitivities are regulated primarily by shortwave radiation, wind speed, and geographic location, particularly latitude and longitude. Our findings reveal nonlinear and scale‐dependent lake–climate interactions driven by competing physical processes, advancing mechanistic understanding of lake thermal responses to ongoing climate warming.