Core Insights - On September 17, Shanghai set three meteorological records, with the highest temperature reaching 37.3°C, marking the latest hot day in the city's history [1] - As of September 17, the total number of high-temperature days this year has reached 53, making it the second highest since records began in 1873 [1] - The number of high-temperature days in September has reached 8, the highest for the month [1] Weather Patterns - A significant cold air mass is approaching, leading to intense interactions between warm and cold air in Shanghai [1] - Strong convective weather was observed in the northern and central parts of Shanghai, with hail approximately 1 cm in diameter reported in several districts [1] - The forecast indicates that high temperatures above 35°C will be rare in the next 10 days, with increased rainfall expected due to the influence of eastern sea air currents [1] Tropical Activity - The Central Meteorological Observatory predicts that 2 to 3 typhoons may form in the South China Sea and the Northwest Pacific region due to active tropical convection [1]