Nantong is located in the alluvial plain of the lower reaches of the Yangtze  River. The marine climate is obvious. The annual average temperature is 15.1 degrees centigrade and the annual precipitation is about 1040 millimeters. The climate is mild, the four seasons are distinct, and the spring and autumn are relatively short.

Nantong belongs to the humid climate area of the north subtropical zone. The influence of monsoon is obvious. There are four distinct seasons in Nantong, with mild climate, abundant sunshine and rainwater, and long frost-free period. According to the statistics of the last 30 years, the annual average temperature is about 15 degrees Celsius, the annual average sunshine hours are 2000-2200 hours, the annual average precipitation is 1000-1100 mm, and the summer rainfall accounts for 40-50% of the annual rainfall in the same season. The average annual period of rainy day is about 120 days, and there is often a period of plum rain from June to July.