2025年8月20日8时10分，北京市气象台继续发布暴雨蓝色预警信号。预计20日傍晚至21日夜间，我市有雷阵雨天气，部分地区小时雨量可达30毫米以上， 6小时累计雨量可达50毫米以上，山区及浅山区可能出现山洪、泥石流、滑坡等次生灾害，低洼地区可能出现积水，请注意防范。 市气象台20日7时发布：今天白天晴转阴有分散性阵雨或雷阵雨，北转南风二三级，最高气温31℃；夜间阴有小到中雨，伴有雷电，南转北风一二级，最 低气温25℃。 此次北方降雨过程 很多时候都是在夜间降雨 有哪些因素会导致夜雨多呢？ 根据中国气象局统计的2005至2023年京津冀地区各城市降水数据显示，7月、8月大多数城市降水多发时段集中在19时至22时。根据京津冀地区各城市7 月、8月不同时段出现降雨的累计日数，可以明显看到多夜雨是华北平原夏季降雨的重要特征之一，这使得公众下班"晚高峰"时段出行常受到降水天气的 影响。 气象专家表示，夜雨产生的关键原因是"夜间西北太平洋副热带高压西侧的低空急流增强"。京津冀地区，位于低空空气辐合区域，由于空气抬升，就容易 出现夜雨的现象。 另外，地形分布对低空急流的强度也有一定影响，在夜间山区空气下沉、平原空气上升， ...

Summary of Key Points Core Viewpoint - The central meteorological forecast indicates significant rainfall across various regions in China, particularly in North China and Northeast China, with warnings for heavy rain and potential geological disasters due to the weather conditions [1][3]. Group 1: Rainfall Patterns - Rainfall is expected to be concentrated in three main areas, with the largest being in North China, where heavy rain and localized torrential rain are anticipated [1]. - Recent observations show strong rainfall in the western and northern parts of Beijing, as well as scattered rain in southern Northeast China [2]. Group 2: Meteorological Factors - The subtropical high-pressure system is currently covering the Huanghuai, Jianghuai, and Jiangnan regions, contributing to ongoing rainfall [3]. - The occurrence of night rain in North China is attributed to the enhancement of low-level jet streams on the western side of the subtropical high-pressure system [6]. - Statistical data from the China Meteorological Administration indicates that the majority of rainfall in the Beijing-Tianjin-Hebei region occurs between 7 PM and 10 PM during July and August, highlighting the prevalence of night rain [4]. Group 3: Impact on Daily Life - The characteristics of summer convective rainfall increase the likelihood of rain during peak commuting hours, particularly in the afternoon to evening and late night to early morning [8]. - The geographical distribution affects the intensity of low-level jets, with nighttime conditions in mountainous areas leading to increased rainfall in plains due to temperature gradients [9]. - Meteorological authorities advise the public to stay updated on weather forecasts and to exercise caution while driving at night due to potential rain [9].