Mechanisms of the record-breaking winter–spring drought over South China in 2024–2025

Abstract South China experienced an unprecedented persistent winter–spring drought during 2024/2025, lasting from November to April and representing the most severe drought event in the past six decades. This extreme drought event caused significant agricultural damage, economic losses, and widespread water shortages. Our analysis reveals that this event was closely linked to persistent atmospheric circulation anomalies extending from winter into the following spring. During this period, anomalous northerly winds in the lower troposphere transported cold and dry air from higher latitudes into South China. Meanwhile, a pronounced and sustained anomalous subsidence suppressed local convective activity, reinforcing drought persistence. Numerical experiments demonstrate that sea surface temperature (SST) warming anomalies in the tropical western Pacific enhanced the regional Hadley circulation, intensifying subsidence over South China and strengthening the northerly wind anomalies. These processes jointly facilitated the development and maintenance of the drought. Overall, our findings underscore the important contribution of tropical SST anomalies in regional-scale extreme drought events and provide valuable insights for improving prediction and risk management of similar extremes in a warming climate.