The People's Republic of China is a vast country with a range of climates varying from tropical to cold temperate and from high mountain to desert.
The climate of China is dominated by the great seasonal wind reversal called the Asiatic monsoon. From October until April winds tend to blow out from China and the heart of Asia under the influence of the great high-pressure system which develops in Siberia and central Asia. From May until September or October, as the continent of Asia heats up, this area becomes one of low pressure and winds are drawn into China, both from the Indian Ocean and the Pacific. These warm moist winds bring most of the annual rainfall to China.
The second important control over the Chinese climate is latitude. Whilst most of the country has warm or hot summers there is a great difference in winter temperatures both from north to south and from the western provinces to the eastern coastal regions. North China, including Manchuria, has extremely cold winters of almost Siberian severity.
For descriptions of the weather and climate of China, the country is split into the following major climatic regions: north-east China including Manchuria, Central China, south China, south-west China, Tibet, Sinkiang and the western interior, and Inner Mongolia.
North-east China including Manchuria
This region broadly consists of the great lowland area of the Hwang Ho valley, part of Inner Mongolia and the whole of Manchuria. Winters are very cold with frequent light snow and much frost. Temperatures as low as -33 °C have been recorded, but a more typical winter daily maximum temperature is about -4 °C. The strong winds often raise clouds of dust which can be very troublesome. There is a rapid decrease in both winter and summer temperatures northwards so that in northern Manchuria rivers are frozen for anything up to six months. Summers are warm and humid over much of the area and may be rather uncomfortable. Summer rainfall is almost everywhere sufficient for cultivation but tends to be unreliable; in some years drought can be a problem. The most unpleasant features of the climate are the summer humidity and the cold, increased by wind chill in winter.
Although the main rainy season is summer, there is some rain throughout the year and the winter weather is more changeable than north China. There are periods of wet weather, alternating with cold spells during which frost and snow occur. This variable winter weather is not unlike that experienced in parts of western Europe and the mid-Atlantic States of the USA. Summer weather is usually warm and humid as damp air moves in from the Pacific. The heat and humidity can sometimes be uncomfortable. The coastal regions occasionally receive very heavy rainfall from typhoons (tropical cyclones) which intensify in the South China Sea and move north-eastwards along the coast. Further inland in central China there is a region in the middle and upper Yangtze valley where winters are distinctly milder and the summers receive less rain. This area has a more pleasant climate as winter snow and frost are less frequent and summer humidity is less uncomfortable.
This region is partly within the tropics and is the warmest and wettest part of the country in summer. Rainfall is very heavy between May and September along the coast, and abundant inland. Winters are mild and frost is almost unknown. The summer heat and humidity can be very uncomfortable. Typhoons are frequent here and may bring strong wind and very heavy rain for a few days at a time to the coastal regions. These are most frequent from July to October.
This inland region along the border with Vietnam and Laos is hilly and mountainous. Summer temperatures are a little moderated by altitude, but winters are generally warm to mild with much sunshine and very little rain. Only rarely does cold air penetrate here from the north, bringing occasional frost at higher levels. Summers are wet at higher levels, but in sheltered valleys the rainfall is not excessive. This region has the most pleasant weather and climate in China around the year.
Tibet is a region of high plateaux and encircling mountains situated in the south centre of China. Its southern boundary includes the highest peaks of the Himalayan mountains (including Everest). Most of the region is above 12,000 feet and there are some extensive areas above 16,000 feet. Winters are severe with frequent light snow and hard frosts. Considering the altitude, summer temperatures are surprisingly warm by daytime, but there is a very sharp drop at night. Most of the precipitation is rain during the summer, when moist air is drawn into Tibet by the Asian monsoon winds. In the west and north of Tibet some snow occurs, but the permanent snowline is surprisingly high at about 20,000 feet. Apart from the low temperatures, strong winds, which accentuate wind chill, are the worst feature of the climate.
Sianking and the Western Interior
This remote and sparsely populated region is almost entirely desert. It has a continental type of climate with cold winters and hot summers. The very sparse precipitation is well distributed through the year. Humidity is low throughout the year and the climate is generally healthy; the principal hazards are very low temperatures accompanied by strong winds in winter and occasional very high temperatures in summer.
Situated to the north and east of Sinkiang, this is a region of mountain ranges and extensive semi-desert lowlands. It has an extreme continental type of climate with very cold winters and warm summers. The sparse precipitation is well distributed throughout the year. The summers are somewhat cooler than Sianking but winters are even colder, resembling those of Manchuria and north China. The ground is snow-covered for up to 150 days a year. Strong winds in winter and spring often raise great clouds of dust which are blown eastwards into north China. This is one of the more unpleasant features of the climate, and the severe winters make warm clothing essential with the wind chill making it feel even colder.