Nam Co (Heavenly Lake) not only responds sensitively to climate change, but also exerts significant influences on climate change. Previous studies revealed that the lake effects from the North American Great Lakes shown interaction with climate changes. However, the lakes effect of more than 1200 lakes with an area of 47,000 km(2) on the Tibetan Plateau remains less studied. In this study, we analyzed the spatial distribution of precipitation in the Nam Co Basin during July-August and November-December to clarify the lake effect. We found that the lake cooling effect during July-August and lake heating effect during November-December resulted in the spatial differences of precipitation within the Nam Co Basin. These effects generally caused more precipitation in the south than in the north during July-August, and more precipitation in the east than in the west during November-December. Weakening Indian monsoon and climate warming led to an increased north-south precipitation difference in the Nam Co Basin. However, the precipitation differences between the west and east during November-December decreased with climate warming. The intensification of the westerly might be responsible for the particular phenomenon. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.