今天上半夜起，上海转为阴有时有雨的天气，并延续到明天白天，局部累积雨量可达中到大雨，明天夜 里转为阴到多云。明日气温9~12℃，上午起东北风4~5级沿江沿海地区阵风6级，相对湿度95%~85%， 体感较阴冷。 这一周，上海雨多晴少，除周三以外，都有雨相伴，比较明显的降水时段在周四和周日，请大家随身携 带雨具。气温起伏不大，最高气温在12~15℃之间，最低气温7~11℃，体感偏阴冷，防寒保暖不能松 懈。 智通财经记者 陈悦 明天（2月24日）是春节假期后的首个工作日，上海阴有时有雨，局部累积中到大雨，上班注意交通安 全。 上海市气象服务中心介绍，今天（2月23日），上海上午阳光开场，下午云系逐渐增多。在冷空气影响 下，气温较昨日明显下滑，各区白天最高气温在13~16℃之间，市区徐家汇站定格在15.4℃。风力较 强，局部最大风力达6~7级，多区发布大风蓝色预警信号，风寒效应明显。 ...

Group 1 - The core point of the article discusses the weather conditions in Shanghai, highlighting the occurrence of fog with visibility less than 500 meters due to radiation cooling and moist air from the southeast wind [1][3] - On January 16, the fog gradually dissipated by noon, with daytime temperatures reaching around 19 to 20 degrees Celsius, specifically noting a high of 19.7 degrees Celsius at the Xujiahui station [1] - The weather forecast indicates a significant temperature drop next week due to strong cold air, with expected temperatures between 3 to 5 degrees Celsius and potential light rain or snow on January 17 and 18 [3]

Group 1 - Shanghai's temperature is experiencing a slight rise today, with the lowest temperature recorded at 5.3℃ in the city, while some districts dropped below freezing [1] - A cold air mass is expected to bring temperatures back down below 10℃ tomorrow, with highs only reaching between 2℃ and 7℃, and lows in suburban areas dropping to between -4℃ and -2℃ [1] - Next week, after a cold start on Monday with temperatures around 1℃, a significant warming trend is forecasted, with temperatures rising to 16℃-17℃ by midweek [4] Group 2 - The upcoming warm spell is described as a "retaliatory warming" during the coldest period of winter, which is somewhat unusual but has been observed in the context of global warming [6] - Historical data indicates that extreme temperature records in January have previously exceeded 20℃ in Shanghai, suggesting that such warm spells can precede subsequent cold fronts [6] - The weather will remain dry, with relative humidity dropping to as low as 20%, indicating a need for hydration and caution regarding fire and electrical safety at home [6]