Reservoirs are an essential part of modern society, serving a variety of critical functions while exerting an uncertain and debatable impact on the surrounding climate and environment. The precipitation‐temperature coupling relationship and the associated compound extreme events are critical climatic factors for humans and ecosystems, but how reservoirs would affect these factors is unknown. Here, we found that sites near reservoirs had higher sensitivity of precipitation extremes to temperature increases, as well as an increased frequency of compound precipitation‐temperature extreme events, based on a global‐scale analysis of reservoir and meteorological observations and a paired comparison approach. Additionally, these reservoir climate effects are closely correlated with reservoir size and are more pronounced in warm‐dry climates. It highlights the potential climate risks associated with reservoirs which have important implications for strengthening a community's resilience in the face of these challenges. Plain Language Summary The interactive effects of reservoirs on changes in meteorological variables have a great impact on the local community, including water security, energy production, and agriculture. Previous studies have focused on changes in individual variables such as precipitation or temperature, which however are interconnected; these individual variables do not fully represent the many changes that can occur as a result of reservoir construction. This study conducted a global scale analysis based on observations, for the first time, quantifying the changes in the precipitation‐temperature coupling features caused by reservoirs. The results show significant differences between sites near and far from reservoirs in the sensitivity of precipitation extremes to temperature increases, as well as the frequency of compound hot‐wet and hot‐dry events. The effects of large reservoirs in warm and dry regions were most pronounced, leading to increased compound precipitation‐temperature extreme events. Given that the construction of additional dams is regarded as one of the best available options for meeting future increases in water and energy demands, these findings aid in anticipating and mitigating any adverse effects of reservoirs on local climate and have important implications for regional climate prediction under the influence of human activities. Key Points This study presents the first global‐scale analysis of changes in precipitation‐temperature coupling relationships caused by reservoirs Reservoirs intensify the sensitivity of precipitation extremes to temperature and frequency of compound precipitation‐temperature extremes Reservoirs have the most pronounced climate impacts in warm and arid regions