Shanghai is one of the four direct-controlled municipalities of China and the most populous city proper in the world with a population of more than 24 million as of 2014. It is a globalfinancial centre and transport hub, with the world's busiest container port. Located in the Yangtze River Delta, it sits on the south edge of the estuary of the Yangtze in the middle portion of the East China coast. The municipality borders the provinces ofJiangsu and Zhejiang to the north, south and west, and is bounded to the east by the East China Sea.
As a major administrative, shipping and trading city, Shanghai grew in importance in the 19th century due to trade and recognition of its favourable port location and economic potential. The city was one of five treaty ports forced open to foreign trade following the British victory over China in the First Opium War. The subsequent 1842 Treaty of Nanking and 1844 Treaty of Whampoa allowed the establishment of the Shanghai International Settlement and theFrench Concession. The city then flourished as a centre of commerce between China and other parts of the world (predominantly Western countries), and became the primary financial hub of the Asia-Pacificregion in the 1930s. However, with the Communist Party takeover of the mainland in 1949, trade was limited to other socialist countries, and the city's global influence declined. In the 1990s, the economic reforms introduced by Deng Xiaoping resulted in an intense re-development of the city, aiding the return of finance and foreign investment to the city.
Shanghai has been described as the "showpiece" of the boomingeconomy of mainland China; renowned for its Lujiazui skyline, and museums and historic buildings, such as those along The Bund, as well as the City God Temple and the Yu Garden.
Shanghai has a humid subtropical climate (Köppen Cfa) and experiences four distinct seasons. Winters are chilly and damp, with northwesterly winds from Siberia can cause nighttime temperatures to drop below freezing, although most years there are only one or two days of snowfall. Summers are hot and humid, with an average of 8.7 days exceeding 35 °C (95 °F) annually; occasional downpours or freak thunderstorms can be expected. The city is also susceptible to typhoons in summer and the beginning of autumn, none of which in recent years has caused considerable damage. The most pleasant seasons are spring, although changeable and often rainy, and autumn, which is generally sunny and dry. The city averages 4.2 °C (39.6 °F) in January and 27.9 °C (82.2 °F) in July, for an annual mean of 16.1 °C (61.0 °F). With monthly percent possible sunshine ranging from 34% in March to 54% in August, the city receives 1,895 hours of bright sunshine annually. Extremes since 1951 have ranged from −10.1 °C (14 °F) on 31 January 1977 (unofficial record of −12.1 °C (10 °F) was set on 19 January 1893) to 39.9 °C (104 °F) on 6 and 8 August 2013. A highest record of 40.9 °C (106 °F) was registered in Xujiahui, a downtown station on 21 July 2017.