Nancheng County has a
humid subtropical climate (
Köppen Cfa), with long, humid, very hot summers and cool and drier winters with occasional cold snaps. The monthly 24-hour average temperature ranges from in January to in July, with an annual mean of ; the frost-free period lasts 265 days. The average annual precipitation is around . Winter begins somewhat sunny and dry but becomes progressively wetter and cloudier; spring begins especially gloomy, and from March to June each of the months averages more than of rainfall. After the heavy rains subside in June, summer is especially sunny. Autumn is warm to mild and relatively dry. With monthly percent possible sunshine ranging from 20% in March to 58% in July, the county receives 1,635 hours of bright sunshine annually. ==Transportation==