Temperature extremes have been related to anomalies in the large-scale circulation, but how these alter the surface energy balance is less clear. Here, we attributed extremes in daytime and nighttime temperatures of the eastern Tibetan Plateau to anomalies in the surface energy balance. We find that daytime temperature extremes are mainly caused by altered solar radiation, while nighttime extremes are controlled by changes in dowelling longwave radiation. These radiation changes are largely controlled by cloud variations, which are further associated with certain large-scale circulations through modulating vertical air motion and horizontal cloud convergence. Anomalies in heat advection, soil moisture, and snow albedo played secondary roles in triggering the initial change and contributed mostly to maintaining the duration. These mechanisms are consistent during winter and summer, also holding for cold extremes. Our work implies more frequent and severe warm nights and compound warm events over the Tibetan Plateau in the future.