我国已进入拉尼娜状态，今年冬天是冷还是热？

Core Viewpoint - The article discusses the current La Niña phenomenon in China, its implications for winter weather, and the potential for drought conditions in the winter and spring seasons [1][5][7]. Group 1: La Niña Status and Events - La Niña is characterized by a significant and sustained cooling of sea surface temperatures in the central and eastern equatorial Pacific [1][3]. - The La Niña state is defined by the Niño 3.4 index falling below -0.5°C for at least five consecutive months to be classified as a La Niña event [3]. - La Niña phenomena occur every two to seven years, with increased frequency in recent years attributed to complex global warming mechanisms [3]. Group 2: Weather Predictions and Impacts - The current La Niña state is expected to lead to reduced precipitation in southern China, particularly in December, with a higher likelihood of cold air events causing temperature fluctuations [5][8]. - Experts predict a low probability of a double La Niña event this winter, which refers to consecutive winters experiencing La Niña conditions [3][7]. - The article highlights that while La Niña can influence winter temperatures, it is not the sole determinant, as other factors like Arctic sea ice and atmospheric circulation also play significant roles [8][9]. Group 3: Specific Regional Impacts - The likelihood of winter drought conditions in East and South China is noted, with potential for significant impacts on agriculture and water resources [7][10]. - In regions like Guizhou, which frequently experiences freezing rain, the probability of widespread low-temperature rain and snow events this winter is expected to be relatively low [12]. - The article emphasizes the need for preparedness against low-temperature and freezing rain disasters, particularly in high-risk areas [10].