Abstract: This study focuses on AHT (abnormal high-temperature) events during midsummer in Hunan Province. Using statistical analyses and dynamical diagnostic methods, the authors investigated the characteristics of these events and the mechanisms underlying their formation. The findings show a significant increasing trend in AHT events in Hunan. These events are closely associated with the strengthening and eastward expansion of the South Asian High and the northward and westward extension of the Western Pacific Subtropical High. The coupling of these two high-pressure systems establishes a stable circulation pattern that inhibits the southward intrusion of cold air, enhances subsidence, suppresses cloud formation and precipitation, and promotes abnormal surface warming. The descending motion within the high-pressure region produces pronounced adiabatic warming, which is the dominant contributor to regional high temperatures. Further analysis identifies two wave trains: one originating from the mid-to-high latitudes of northwestern Asia and the other from the low latitudes to the southeast. These wave trains propagate toward northern Hunan and the surrounding region, where wave activity flux convergence favors the development and intensification of abnormal low-pressure circulation to the north and abnormal high-pressure circulation over Hunan. The combined influence of mid- to high-latitude circulation systems and low-latitude wave trains strengthens the abnormal high pressure over Hunan and enhances subsiding motion. The resulting anomalous adiabatic warming contributes to the occurrence and intensification of regional high-temperature events.