Per annum, and that of the east coast, where the north-east monsoon breaks with all its fury, is usually about 1 55 in.
The south-westerly winds which prevail north of the equator during the hot half of the year, to which navigators have given the name of the south-west monsoon (the latter word being a corruption of the Indian name for season), arise from the great diminution of atmospheric pressure over Asia, which begins to be strongly marked with the great rise of temperature in April and May, and the simultaneous relatively higher pressure over the equator and the regions south of it.
Thus the south-west monsoon begins in the Arabian Sea with west and north-westerly winds,which draw round as the year advances to south-west and fall back again in the autumn by northwest to north.
In the Bay of Bengal the strength of the southwest monsoon is rather from the south and south-east, being succeeded by north-east winds after October, which give place to northerly and north-westerly winds as the year advances.
The south-west monsoon does not generally extend, in its character of a south-west wind, over the land.
The diurnal mountain winds are very strongly marked on the Himalaya, where they probably are the most active agents in determining the precipitation of rain along the chain - the monsoon currents, as before stated, not penetrating among the mountains.
To be the fall at Peking; while at Canton, which lies nearly on the northern tropic and the region of the south-west monsoon is entered, the quantity is increased to 78 in.
The rainfall of the province is considerably heavier than in northern India, and the result of this is a cooler and more pleasant atmosphere during the monsoon season.
Four seasons are recognized - January - April, very dry and great heat; May - June, cooler and the " heavy " rains; July - September, the season of extreme heat and the south-west monsoon; October - December, the " light " rains.
During the north-east monsoon, from the middle of October to the middle of April, dry weather prevails and the thermometer averages from 77° to 80° F.
During the southwest monsoon, from the middle of April to the middle of October, rain falls daily and the temperature varies between 85° and 95°.
The flora of Siberia presents very great local varieties, not only on account of the diversity of physical characteristics, but also in consequence of the intrusion of new species from the neighbouring regions, as widely different as the arctic littoral, the arid steppes of Central Asia, and the wet monsoon regions of the Pacific littoral.
The influence of the monsoon is greatly moderated before it reaches this region, and the rains sometimes fail altogether.
In Annam the rainy season begins during September and lasts for three or four months, corresponding with the northeast monsoon and also with a period of typhoons.
The southwest monsoon which brings rain in Cochin-China coincides with the dry season in Annam, the reason probably being that the mountains and lofty plateaus separating the two countries retain the precipitation.
Its mountains are insufficient in elevation and extent to attract their full share of the monsoon rains, which fall so abundantly on the Abyssinian highlands on the other side of the Red Sea; for this reason Arabia has neither lakes nor forests to control the water-supply and prevent its too rapid dissipation, and the rivers are mere torrent beds sweeping down occasionally in heavy floods, but otherwise dry.
Of Aden, the summer heat is tempered by the monsoon winds, and the seasonal variation of temperature is less marked.
This appears to be about the northern limit reached by the south-west monsoon, which from June to September brings a fairly abundant rainfall to the Yemen highlands, though the Tehama remains almost entirely rainless.
Dobbo, on a small western island, is the chief place; its resident population is reinforced annually, at the time of the west monsoon, by traders from that quarter, who deal in the tripang, pearl shell, tortoise-shell, and other produce of the islands.
On the northern shore of Hong-Kong there is a patent slip at East or Matheson Point, which is serviceable during the north-east monsoon, when sailing vessels frequently approach Victoria through the Ly-ee-mun Pass.
Sea-snakes occasionally make their way to Japan, being cairied thither by the Black Current (Kuro Shiwo) and the monsoon, but they must be regarded as merely fortuitous visitors.
In winter, for example, when the northern monsoon begins to blow, numbers of denizens of the Sea of Okhotsk swim southward to the more genial waters of north Japan; and in summer the Indian Ocean and the Malayan archipelago send to her southern coasts a crowd of emigrants which turn homeward again at the approach of winter.
These, like the mollusca, indicate the influence of the Kuro Shiwo and the south-west monsoon, for they have close affinity with species found in the Indian and Pacific Oceans.
In the monsoon regions the half-yearly change from on-shore to off-shore winds produces noticeable differences in XIX.
At this period an exact knowledge of the depths of the ocean off after the beginning of the south-west monsoon to a minimum assumed an unlooked-for practical importance from the daring in August, the total range being 92 in.
During the monsoon the climate is very damp, and at times even cold and raw, thick clouds and mist enveloping the sky for many days together.
On the Swahili coast the south-east monsoon begins in April and the northeast monsoon in November.
Rain comes with the south-east monsoon, and on the northern part of the coast the rainy season is divided into two parts, the great and the little Masika: the former falls in the months of September, October, November; the latter in February and March.
The slopes of the plateau which face the rain-bringing monsoon are in some places covered with primeval forest, in which timber is plentiful.
The wet season - May to October - corresponds with the prevalence of the south-west monsoon in the Bay of Bengal.
The full force of the monsoon is, however, broken by the western frontier hills; and while the rainfall at Mergui is over 180, and at Moulmein 240 in., that of Bangkok seldom exceeds 54, and Chiengmai records an average of about 42 in.
The cool season begins with the commencement of the north-east monsoon in the China Sea in November.
The most striking general fact as regards climate in the archipelago is that wherever that part of the south-east monsoon which has passed over Australia strikes, the climate is comparatively dry, and the vegetation is less luxuriant.
The northwest monsoon, beginning in October and lasting till March, brings the principal rainy season in the archipelago.
Monsoon of southern Asia controls the prevailing winds, its influence extending eastwards to 145° E., near the Ladrones, and southwards to the equator.
In the South Pacific the northwest monsoon of Australia affects a belt running east of New Guinea to the Solomon Islands.
Within the southern monsoon region there is a gradual transition to the northwest monsoon of New Guinea in low latitudes, and in higher latitudes to the north-east wind of the Queensland coast.
The characteristic feature of the south-western Pacific is therefore the relatively low pressure and the existence of a true monsoon region in the middle of the tradewind belt.
It is to be noted that the climate of the islands of the Pacific becomes more and more healthy the farther they are from the monsoon region.
The surface currents of the Pacific have not been studied in the same detail as those of the Atlantic, and their seasonal variations Circulation are little known except in the monsoon regions.
The Equatorial CounterCurrent flowing eastwards is largely assisted during the latter half of the year by the south-west monsoon, and from July to October the south-west winds prevailing east of 150° E.
On reaching the western Pacific part of this current passes southwards, east of New Zealand, and again east of Australia, as the East Australian Current, part northwards to join the Equatorial CounterCurrent, and during the north-east monsoon part makes its way through the China Sea towards the Indian Ocean.
During the south-west monsoon this last branch is reversed, and the surface waters of the China Sea probably unite with the Kuro Siwo.
The wet season, lasting during the prevalence of the south-west monsoon, from April to December, is clearly defined on the Pacific slope.
Owing to its tropical situation and its almost entire dependence upon the monsoon rains, India is more liable than any other country in the world to crop failures, which upon occasion deepen into famine.
The people depend so entirely upon agriculture, and the harvest is so entirely destroyed by a single monsoon failure, that wherever a total failure occurs the landless labourer is immediately thrown out of work and remains out of work for the whole year.
There are two seasons of rainfall over the province: the monsoon season, when supplies of moisture are brought up by the ocean winds from the Arabian Sea and the Bay of Bengal; and the winter season, when storms advancing eastwards from Persia and the Caspian districts occasion winds, widespread rain and snowfall.
In the two years 1899 and 1900 the monsoon was very weak, the result being a severe famine which caused great mortality among the Bhil population.
Tibet is affected by the south-west monsoon, just as the Pamirs are affected, but in varying degrees according to geographical position.
Along the parallel of 33° N., and arrests the monsoon currents), is subject to much the same climatic influences as the eastern Himalaya.