Editing Monsoon (section)

=== Asia ===
The Asian monsoons may be classified into a few sub-systems, such as the Indian Subcontinental Monsoon which affects the Indian subcontinent and surrounding regions including Nepal, and the East Asian Monsoon which affects southern China, [[Taiwan]], Korea and parts of Japan.

==== South Asian monsoon ====
{{Main|Monsoon of South Asia}}

=====Southwest monsoon=====
[[File:India southwest summer monsoon onset map en.svg|thumb|Onset dates and prevailing wind currents of the southwest summer monsoons in India]]

The southwestern summer monsoons occur from June through September. The [[Thar Desert]] and adjoining areas of the northern and central Indian subcontinent heat up considerably during the hot summers. This causes a low pressure area over the northern and central Indian subcontinent. To fill this void, the moisture-laden winds from the Indian Ocean rush into the subcontinent. These winds, rich in moisture, are drawn towards the [[Himalayas]]. The Himalayas act like a high wall, blocking the winds from passing into Central Asia, and forcing them to rise. As the clouds rise, their temperature drops, and [[Orographic precipitation|precipitation occurs]]. Some areas of the subcontinent receive up to {{convert|10000|mm|in|abbr=on}} of rain annually.

The southwest monsoon is generally expected to begin around the beginning of June and fade away by the end of September. The moisture-laden winds on reaching the southernmost point of the [[Indian subcontinent|Indian Peninsula]], due to its topography, become divided into two parts: the ''Arabian Sea Branch'' and the ''Bay of Bengal Branch''.

The ''Arabian Sea Branch'' of the Southwest Monsoon first hits the [[Western Ghats]] of the coastal state of [[Kerala]], India, thus making this area the first state in India to receive rain from the Southwest Monsoon. This branch of the monsoon moves northwards along the Western Ghats ([[Konkan]] and [[Goa]]) with precipitation on coastal areas, west of the Western Ghats. The eastern areas of the Western Ghats do not receive much rain from this monsoon as the wind does not cross the Western Ghats.

The ''Bay of Bengal Branch'' of Southwest Monsoon flows over the [[Bay of Bengal]] heading towards north-east India and [[Bengal]], picking up more moisture from the Bay of Bengal. The winds arrive at the [[Himalaya|Eastern Himalayas]] with large amounts of rain. [[Mawsynram]], situated on the southern slopes of the [[Khasi Hills]] in [[Meghalaya]], India, is one of the wettest places on Earth. After the arrival at the Eastern Himalayas, the winds turns towards the west, travelling over the [[Indo-Gangetic Plain]] at a rate of roughly 1–2 weeks per state,<ref>{{Cite book|url=https://books.google.com/books?id=Pz_xAwAAQBAJ&pg=PA28|title=Weather and Climate: India in Focus|last=Explore|first=Team|date=2005|publisher=EdPower21 Education Solutions|page=28}}</ref> pouring rain all along its way. June 1 is regarded as the date of onset of the monsoon in India, as indicated by the arrival of the monsoon in the southernmost state of Kerala.

The monsoon accounts for nearly 80% of the rainfall in India.<ref>{{Cite book|url=https://books.google.com/books?id=vdFBDwAAQBAJ&pg=PA121|title=Experimental Agrometeorology: A Practical Manual|last1=Ahmad|first1=Latief|last2=Kanth|first2=Raihana Habib|last3=Parvaze|first3=Sabah|last4=Mahdi|first4=Syed Sheraz|date=2017|publisher=Springer|isbn=978-3-319-69185-5|page=121}}</ref><ref>{{Cite news|url=https://weather.com/en-IN/india/monsoon/news/2018-06-27-india-southwest-northeast-monsoon|title=Why India's Twin Monsoons Are Critical To Its Well-Being {{!}} The Weather Channel|work=The Weather Channel|access-date=2018-09-05|language=en-US|archive-date=2018-09-05|archive-url=https://web.archive.org/web/20180905181534/https://weather.com/en-IN/india/monsoon/news/2018-06-27-india-southwest-northeast-monsoon|url-status=dead}}</ref> Indian agriculture (which accounts for 25% of the GDP and employs 70% of the population) is heavily dependent on the rains, for growing crops especially like [[cotton]], [[rice]], [[oilseeds]] and coarse grains. A delay of a few days in the arrival of the monsoon can badly affect the economy, as evidenced in the numerous droughts in India in the 1990s.

The monsoon is widely welcomed and appreciated by city-dwellers as well, for it provides relief from the climax of summer heat in June.<ref>Official Web Site of District Sirsa, India. [http://sirsa.gov.in/htfiles/location.html District Sirsa.] {{webarchive|url=https://web.archive.org/web/20101228153903/http://sirsa.gov.in/htfiles/location.html |date=2010-12-28 }} Retrieved on 2008-12-27.</ref> However, the roads take a battering every year. Often houses and streets are waterlogged and slums are flooded despite drainage systems. A lack of city infrastructure coupled with changing climate patterns causes severe economic loss including damage to property and loss of lives, as evidenced in the [[2005 Maharashtra floods|2005 flooding in Mumbai]] that brought the city to a standstill. [[Bangladesh]] and certain regions of India like [[Assam]] and [[West Bengal]], also frequently experience heavy floods during this season. Recently, areas in India that used to receive scanty rainfall throughout the year, like the [[Thar Desert]], have surprisingly ended up receiving floods due to the prolonged monsoon season.

The influence of the Southwest Monsoon is felt as far north as in China's [[Xinjiang]]. It is estimated that about 70% of all precipitation in the central part of the [[Tian Shan|Tian Shan Mountains]] falls during the three summer months, when the region is under the monsoon influence; about 70% of that is directly of "cyclonic" (i.e., monsoon-driven) origin (as opposed to "[[convection rain|local convection]]").<ref>{{Cite book |last=Blumer |first=Felix P. |year=1998 
|contribution=Investigations of the precipitation conditions in the central part of the Tianshan mountains
|editor-last=Kovar |editor-first=Karel |publisher=International Association of Hydrological Sciences
|isbn=978-1-901502-45-9 |title=Hydrology, water resources and ecology in headwaters. Volume 248 of IAHS publication
|url= http://iahs.info/redbooks/a193/iahs_193_0343.pdf
|pages=343–350}}<!-- |bookurl=https://books.google.com/books?id=SBSygC_IHHIC --></ref> The effects also extend westwards to the Mediterranean, where however the impact of the monsoon is to induce drought via the [[Rodwell-Hoskins mechanism]].<ref>{{cite journal |last1=Rodwell |first1=Mark J. |last2=Hoskins |first2=Brian J. |title=Monsoons and the dynamics of deserts |journal=Quarterly Journal of the Royal Meteorological Society |date=1996 |volume=122 |issue=534 |pages=1385–1404 |doi=10.1002/qj.49712253408 |bibcode=1996QJRMS.122.1385R |url=https://doi.org/10.1002%2Fqj.49712253408 |language=en |issn=1477-870X}}</ref>

{{Multiple image
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| image1            = Bhawal National Park.jpg
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| image2            = Into the green, Bhawal National Park.jpg
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| footer            = Extreme difference is very much evident between wet and dry seasons in tropical seasonal forest. The image at left is taken at [[Bhawal National Park]] in central Bangladesh during dry season, and the right one is taken in wet monsoon season.
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=====Northeast monsoon=====
[[File:(1) Agriculture and rural farms of India.jpg|thumb|Monsoon clouds in [[Madhya Pradesh]]]]

Around September, with the sun retreating south, the northern landmass of the Indian subcontinent begins to cool off rapidly, and air pressure begins to build over northern India. The Indian Ocean and its surrounding atmosphere still hold their heat, causing cold wind to sweep down from the [[Himalayas]] and [[Indo-Gangetic Plain]] towards the vast spans of the Indian Ocean south of the [[Deccan Plateau|Deccan]] peninsula. This is known as the Northeast Monsoon or Retreating Monsoon.

While travelling towards the Indian Ocean, the cold dry wind picks up some moisture from the [[Bay of Bengal]] and pours it over peninsular India and parts of [[Sri Lanka]]. Cities like [[Chennai]], which get less rain from the Southwest Monsoon, receive rain from this Monsoon. About 50% to 60% of the rain received by the state of [[Tamil Nadu]] is from the Northeast Monsoon.<ref>{{cite web|url=http://www.imdchennai.gov.in/northeast_monsoon.htm|title=NORTHEAST MONSOON|url-status=dead|archive-url=https://web.archive.org/web/20151229133725/http://www.imdchennai.gov.in/northeast_monsoon.htm|archive-date=2015-12-29|access-date=2011-11-07}}</ref> In Southern Asia, the northeastern monsoons take place from October to December when the surface [[high-pressure system]] is strongest.<ref>{{cite book|url=https://books.google.com/books?id=Zhbqbrg2XswC&q=characteristics+of+an+oceanic+climate+koppen&pg=PA203|title=Climatology|author1=Robert V. Rohli |author2=Anthony J. Vega |page=204|publisher=Jones & Bartlett Publishers|year=2007|access-date=2009-07-19|isbn=978-0-7637-3828-0}}</ref> The [[jet stream]] in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across southern Asia, creating dry [[air stream]]s which produce clear skies over India. Meanwhile, a low pressure system known as a [[monsoon trough]] develops over [[South-East Asia]] and [[Australasia]] and winds are directed toward Australia. In the Philippines, northeast monsoon is called [[Amihan]].<ref>{{Cite web |last=Arceo |first=Acor |date=2023-10-20 |title=Philippines' northeast monsoon season underway |url=https://www.rappler.com/nation/weather/pagasa-northeast-monsoon-amihan-philippines-start-october-20-2023/ |access-date=2024-01-06 |website=RAPPLER |language=en-US}}</ref>

==== East Asian monsoon ====
{{main|East Asian monsoon}}
[[File:3933Typhoons Krosa Lekima monsoon tidal flooding in Calumpit, Bulacan 13.jpg|thumb|Monsoon floods in the Philippines]]
[[File:A classic summer thunderstorm in Silang, Cavite.jpg|thumb|Monsoonal summer thunderstorm in [[Silang, Cavite]], Philippines]]
The East Asian monsoon affects large parts of [[Indochina]], the [[Philippines]], China, [[Taiwan]], Korea, Japan, and [[Siberia]]. It is characterised by a warm, rainy summer monsoon and a cold, dry winter monsoon. The rain occurs in a concentrated belt that stretches east–west except in East China where it is tilted east-northeast over Korea and Japan. The seasonal rain is known as ''Meiyu'' in China, ''Jangma'' in Korea, and ''Bai-u'' in Japan, with the latter two resembling frontal rain.

The onset of the summer monsoon is marked by a period of premonsoonal rain over South China and Taiwan in early May. From May through August, the summer monsoon shifts through a series of dry and rainy phases as the rain belt moves northward, beginning over [[Indochina]] and the [[South China Sea]] (May), to the [[Yangtze River|Yangtze River Basin]] and Japan (June) and finally to northern China and Korea (July). When the monsoon ends in August, the rain belt moves back to southern China.