How does Jiangsu's climate differ north and south of the old Huai River?

Jiangsu province is divided into two distinct climatic zones by the old Huai River:

• Central and Southern Jiangsu: This region experiences a humid subtropical climate, often referred to as the Yangtze valley climate. It is characterized by distinct seasons, including prolonged rains of summer-monsoon origin that are vital for rice cultivation. In Nanjing, for example, mean temperatures typically range from 36 °F (2 °C) in January to 82 °F (28 °C) in July.1

• Northern Jiangsu: Located north of the old Huai River, this area features a cool, temperate continental climate. It experiences greater temperature extremes compared to the south, with mean January temperatures dropping below 32 °F (0 °C). While winters are colder, summers in the north are as hot as those in the south.1

Across the province, annual precipitation generally increases from north to south, ranging from approximately 32 to 47 inches (800 to 1,200 mm). Additionally, the coastal areas are susceptible to tropical cyclones between late summer and early autumn.1