Although most of China lies within the temperate zone, climate varies greatly with topography. Minimum winter temperatures range from –27° C (–17° F ) in northern Manchuria to –1° C (30° F ) in the North China Plain and southern Manchuria, 4° C (39° F ) along the middle and lower valleys of the Yangtze, and 16° C (61° F ) farther south. Although summer temperatures are more nearly uniform in southern and central China, with a July mean of about 27° C (81° F ), northern China has a shorter hot period and the nights are much cooler.
Rain falls mostly in summer. Precipitation is heaviest in the south and southeast, with Guangzhou receiving more than 200 cm (80 in), and diminishes to about 60 cm (25 in) in north and northeast China, and to less than 10 cm (4 in) in the northwest. Approximately 31% of the total land area is classified as arid, 22% as semiarid, 15% as subhumid, and 32% as humid.