Water temperature strongly dominates biological communities and ecological processes, while it is sensitively influenced by climatic conditions and human activities such as hydropower regulation. Especially in the most vulnerable mountainous areas of Alpine rivers, intermittent hydropower operation results in strong “thermopeaking” effects downstream often associated with the intermittent “hydropeaking” phenomenon. Temporal and spatial variations of the peaking processes are examined in this work through the application of four indicators of sub-daily hydrological and thermal variability to selected watersheds in the Alpine region using a high-resolution dataset. River water temperature response in peaked river gauging stations is analyzed at the catchment scale and over the last three decades. The results allow identifying relevant time and spatial scales of the hydro- and thermo- peaking process, and stimulating a broader view on their potential ecological implications.