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Instrumental data set have revealed several summer precipitation patterns in eastern China, being summarized as "tripole," "dipole" and "coast" modes. The former two have been found to persist at different time scales, leaving the latter unclear in geological records. Here we present 1300‐year hydroclimate records in a tropical maar lake in the southern coast of China using archeal lipid GDGTs, which can reflect lower water redox conditions largely regulated by lake water depth. The down‐core GDGTs reveal a relatively drier condition during the medieval climate anomaly compared to the Little Ice Age, in‐phase with other records in southeast coast of China but opposite to the inland region, hence demonstrating a persistent "coast" mode in eastern China. The thermal state of equatorial Pacific is suggested to play an important role in shaping the "coast" mode by modulating the location and strength of the western Pacific subtropical high and tropical typhoons. Plain Language Summary: Summer precipitations in eastern China affect more than 1 billion people's lives and economic development. It is well‐known that summer precipitations in eastern China show spatial differences. A seesaw pattern of summer precipitations between the southeast coast and the inland region of China, called "coast" mode, has been proposed from modern observations. However, whether this "coast" mode persists in the past remains unexplored. Here, we present a 1300‐year lake‐level record based on GDGTs, a suit of archeal lipids, in a coastal lake of southern China. The result shows a dry medieval climate anomaly and wet Little Ice Age. This result is consistent with other records in southeast coast of China, but in contrast with those in the inland region, thereby proving the persistent of the "coast" mode in the last millennium. The movement of western Pacific subtropical high and tropical typhoon associated with thermal state of the equatorial Pacific could result in this "coast" mode. Key Points: A 1300‐year lake level record based on archeal tetraether lipids in a maar lake on southern coast of ChinaA climate pattern of dry medieval climate anomaly and wet Little Ice Age exists in the southeast coast of ChinaThe thermal state of the equatorial Pacific shapes the coast mode of summer precipitations in eastern China during the last millennium [ABSTRACT FROM AUTHOR]

Fluctuations in monsoonal climate on orbital‐ to millennial‐timescales have had a major impact on vegetation change in East Asia since the last deglaciation. However, the influence of centennial‐scale oscillations on the spatio‐temporal characteristics of vegetation and climate during the last deglaciation remains controversial. We present a well‐dated, decadal‐resolution pollen record from the sediments of annually laminated Lake Xiaolongwan in Northeast Asia, which reveals major orbital‐/millennial‐scale and minor quasi‐periodic, that is, ∼500‐year (yr) cyclic, vegetation changes from ∼19.96 to ∼10.79 Kyr ago (covering the last deglaciation). The ∼500‐yr cycles are characterized by alternations in broadleaved forest/boreal coniferous forest with tundra steppe representing warm and humid/cold and dry phases of the monsoonal climate. This cyclicity may be related to El Niño‐like/La Niña‐like state and low‐latitude atmosphere‐ocean processes, against the background of the long‐term trend of the deglacial climatic evolution. Our findings demonstrate a close relationship between ecosystem succession and climate change on centennial scale. Plain Language Summary: The East Asian monsoon climate influences around 50% of East Asia's land surface and ecosystems. Past dynamics of vegetation and monsoon climate on orbital‐, millennial‐ and centennial‐ scale across East Asia is essential for better understanding the processes and mechanisms of vegetation and climate changes. We present a pollen record from the annually laminated sediments of Lake Xiaolongwan in Northeast China, which demonstrates a significant quasi‐500‐yr cyclic pattern of vegetational changes, stacking on the orbital‐scale trend and millennial events, triggered by shifts in the East Asian monsoon linked to the El Niño–Southern Oscillation. Regional vegetation is not only affected by the deglacial‐ and millennial‐ scale climate changes, but also influenced by ∼500‐yr climate oscillations. These findings show that the regional vegetation responded sensitively to centennial‐scale changes in the monsoon climate. Key Points: Orbital‐scale climate warming is evidenced by alterations in broadleaved forests and boreal coniferous forests with tundra steppeMillennial‐ to centennial‐scale vegetation changes in response to monsoonal climate change in East Asia∼500‐yr vegetation cycles are triggered by East Asian monsoon changes linked to the El Niño‐Southern Oscillation [ABSTRACT FROM AUTHOR]