Due to its large span in latitude, Shaanxi has a variety of climates. Under the Köppen climate classification, the northern parts, including the Loess Plateau, have either a cold arid (Köppen "BWk") or cold semi-arid (Köppen "BSk"), with cold and very dry winters, dry springs and autumns, and hot summers. The area known as Guanzhong is mostly semi-arid, though there are a few areas with a humid subtropical climate (Köppen "Cwa"), with cool to cold winters, and hot, humid summers that often see early-season heatwaves. The southern portion is much more humid and lies in the humid subtropical zone, with more temperate winters and long, hot, humid summers. Annual mean temperature is roughly between , with January temperatures ranging from and July temperatures ranging from .