Abstract: Based on daily wind speed data from 125 meteorological stations in Yunnan Province for 1979–2020 and calculated wind power density (WPD) at 70 m, this study analyzes the temporal and spatial variations in near-surface wind speed and wind energy. The results show that the annual and seasonal average spatial distributions of wind speed and WPD at 70 m roughly align with the Ailao and Gaoligong Mountains as boundaries. The larger wind speed and WPD area is located to the east of the dividing line, while the smaller district is located to the west of this line. Springtime exhibits the highest wind speeds and WPD values, and at some locations, the WPD can even approach 100 W m⁻². The WPD of most stations in Yunnan has exhibited a considerable decreasing trend over the past 42 years in spring, especially in central Yunnan. The first mode of empirical orthogonal decomposition (EOF) of WPD in spring showed a consistent change in the entire area, with a substantial interdecadal variation from strong to weak around 1999. This interdecadal weakening of WPD may be related to the decadal cooling of the atmospheric heat source over the Tibetan Plateau in China after 1999, which caused considerable pressure anomalies over the Tibetan Plateau and its surroundings. It also resulted in an anomalous anticyclonic circulation across the Yunnan region and South China, as well as an anomalous cyclonic circulation over the Bay of Bengal and the Indian Peninsula. The climatological southwest wind was weakened by these anomalies, ultimately leading to interdecadal variation in WPD.