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"Rainy season" redirects here. For the film, seeWet Season (film).For other uses, seeRainy Season (disambiguation).

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The rainfall distribution by month inCairns,Australia

Thewet season(sometimes called therainy seasonormonsoon season) is the time of year when most of a region's average annualrainfalloccurs.[1]Generally, the season lasts at least one month.[2]The termgreen seasonis also sometimes used as aeuphemismby tourist authorities.[3]Areas with wet seasons are dispersed across portions of thetropicsandsubtropics.[4]

Under theKöppen climate classification,fortropical climates,a wet season month is defined as a month where average precipitation is 60 millimetres (2.4 in) or more.[5]In contrast to areas withsavannaclimates andmonsoonregimes,Mediterranean climateshave wet winters and dry summers. Dry and rainy months are characteristic oftropical seasonal forests:in contrast totropical rainforests,which do not have dry or wet seasons, since their rainfall is equally distributed throughout the year.[6]Some areas with pronounced rainy seasons will see a break in rainfall mid-season, when theintertropical convergence zoneormonsoon troughmoves to higher latitudes in the middle of the warm season.[7]

When the wet season occurs during a warm season, orsummer,precipitationfalls mainly during the late afternoon and early evening. In the wet season,air qualityimproves, freshwater qualityimproves, andvegetationgrows substantially, leading to crop yields late in the season. Rivers overflow their banks, and some animals retreat to higher ground.Soilnutrients diminish and erosion increases. The incidence ofmalariaand dengue increases in areas where the rainy season coincides with high temperatures, particularly in tropical areas.[8]Some animals have adaptation and survival strategies for the wet season. Often, the previousdry seasonleads to food shortages in the wet season, as the crops have yet to mature. Crops which can be successfully planted during the wet or rainy season arecassava,maize,groundnut,millet,riceandyam.[9] Thetemperatecounterpart to the tropical wet season isspringorautumn.

Character of the rainfall[edit]

A wet-season storm at night inDarwin,Australia

In areas where the heavy rainfall is associated with a wind shift, the wet season is known as themonsoonseason. Many tropical and subtropical climates experience monsoon rainfall patterns.[10]Rainfall in the wet season is mainly due to daytime heating, which leads to diurnal thunderstorm activity within a pre-existing moist airmass, so the rain mainly falls in late afternoon and early evening in savanna and monsoon regions.

Much of the total rainfall each day occurs in the first minutes of the downpour,[7]before the storms mature into their stratiform stage.[11]Most places have only one wet season, but areas of the tropics can have two wet seasons, because the monsoon trough, orIntertropical Convergence Zone,can pass over locations in the tropics twice per year. However, since rain forests have rainfall spread evenly through the year, they do not have a wet season.[6]

Areas affected[edit]

Monsoon floods inBangladesh
Long-term mean precipitation by month

Areas with asavannaclimate inSub-Saharan Africa,such asGhana,Burkina Faso,[12][13]Darfur,[14]Eritrea,[15]Ethiopia,[16]andBotswanahave a distinct rainy season.[17]Also subtropical areas likeFlorida,SouthandSoutheastTexas, and southernLouisianain theUnited Stateshave a rainy season.[18]Monsoon regions include theIndian subcontinent,Southeast Asia(includingIndonesiaandPhilippines),[19]northern sections ofAustralia,[20]Polynesia,[21]Central America,[22]western and southernMexico,[23]the Desert Southwest of the United States,[24]southernGuyana,[25]and northeastBrazil.[26]

NorthernGuyanahas two wet seasons: one in early spring and the other in early winter.[25]In western Africa, there are two rainy seasons across southern sections, but only one across the north.[27]Within the Mediterranean climate regime, the west coast of the United States, the southwest coast of Australia and South Africa, theMediterraneancoastline of Italy, Spain, Greece,[28]Lebanon, Syria, Algeria, Morocco, Tunisia, and Turkey, as well as areas further inland in Western Asia which include Jordan, Northern Iraq and most parts of Iran, experience a wet season in the winter months.[29]Similarly, the wet season in theNegev desertofIsraelextends from October through May.[30]At the boundary between the Mediterranean and monsoon climates lies theSonoran desert,which receives the two rainy seasons associated with each climate regime.[31]

The wet season is known by many different local names throughout the world. For example, in Mexico it is known as "storm season". Different names are given to the various short "seasons" of the year by the First Nations ofNorthern Australia:the wet season typically experienced there from December to March is calledGudjewg.The precise meaning of the word is disputed, although it is widely accepted to relate to the severe thunderstorms, flooding, and abundant vegetation growth commonly experienced at this time.[32]

Effects[edit]

A monsoon in theVindhyamountain range, centralIndia

In tropical areas, when the monsoon arrives, high daytime high temperatures drop and overnight low temperatures increase, thus reducingdiurnal temperature variation.[33]During the wet season, a combination of heavy rainfall and, in some places such asHong Kong,an onshore wind, improveair quality.[34]

In Brazil, the wet season is correlated with weakertrade windsoff the ocean.[26]ThepHlevel of water becomes more balanced due to the charging of localaquifersduring the wet season.[35]Water also softens, as the concentration of dissolved materials reduces during the rainy season.[36]Erosion is also increased during rainy periods.[7]

Arroyosthat are dry at other times of the year fill with runoff, in some cases with water as deep as 10 feet (3.0 m).[37]Leaching of soils during periods of heavy rainfall depletes nutrients.[37]The higher runoff from land masses affects nearby ocean areas, which are morestratified,or less mixed, due to stronger surface currents forced by the heavy rainfall runoff.[38]

Floods[edit]

High rainfall can cause widespread flooding,[39]which can lead to landslides and mudflows in mountainous areas.[40]Such floods cause rivers to burst their banks and submerge homes.[41]TheGhaggar-Hakra River,which only flows during India's monsoon season, can flood and severely damage local crops.[42]Floods can be exacerbated by fires that occurred during the previous dry season, which cause soils which are sandy or composed ofloamto become hydrophobic, or water repellent.[43]In various ways governments may help people deal with wet season floods. Flood plain mapping identifies which areas are more prone to flooding.[44]Instructions on controlling erosion through outreach[clarification needed]are also provided by telephone or the internet.[45]

Life adaptations[edit]

Equatorialsavannain theEast ProvinceofCameroon

Humans[edit]

The wet season is the main period of vegetation growth within the Savanna climate regime.[46]However, this also means that wet season is a time for food shortages before crops reach their full maturity.[47]This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound.[48]Malaria incidence increases during periods of high temperature and heavy rainfall.[49]

Animals[edit]

Cows calve, or give birth, at the beginning of the wet season.[50]The onset of the rainy season signals the departure of themonarch butterflyfrom Mexico.[51]Tropical species ofbutterfliesshow larger dot markings on their wings to fend off possible predators and are more active during the wet season than thedry season.[52]Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to the rains causes an increase in crocodile nesting.[53]Other species, such as thearroyo toad,spawn within the couple of months after the seasonal rains.[54]Armadillosandrattlesnakesseek higher ground.[55]

See also[edit]

References[edit]

  1. ^"When is rainy season?".Met Office.Retrieved2022-09-02.
  2. ^Glossary of Meteorology (2013).Rainy season.Archived2009-02-15 at theWayback MachineAmerican Meteorological Society. Retrieved on 2008-12-27.
  3. ^Costa Rica Guide (2005).When to Travel to Costa Rica.Archived2012-03-15 at theWayback MachineToucanGuides. Retrieved on 2008-12-27.
  4. ^Michael Pidwirny (2008).CHAPTER 9: Introduction to the Biosphere.PhysicalGeography.net. Retrieved on 2008-12-27.
  5. ^"Updated world Köppen-Geiger climate classification map"(PDF).
  6. ^abElisabeth M. Benders-Hyde (2003).World Climates.Blue Planet Biomes. Retrieved on 2008-12-27.
  7. ^abcJ. S. 0guntoyinbo and F. 0. Akintola (1983).Rainstorm characteristics affecting water availability for agriculture.Archived2009-02-05 at theWayback MachineIAHS Publication Number 140. Retrieved on 2008-12-27.
  8. ^"Malaria Fact Sheet".The World Health Organization.April 2016.RetrievedApril 24,2016.
  9. ^"6 Types Of Crops To Plant During Rainy Season".agricfy.com.2021-07-28.Retrieved2022-10-01.
  10. ^Glossary of Meteorology (2009).Monsoon.Archived2008-03-22 at theWayback MachineAmerican Meteorological Society. Retrieved on 2009-01-16.
  11. ^Robert A. Houze Jr (1997).Stratiform Precipitation in Regions of Convection: A Meteorological Paradox?Bulletin of the American Meteorological Society, pp. 2179. Retrieved on 2008-12-27.
  12. ^Patrick Laux et al. (2008): Predicting the regional onset of the rainy season in West Africa. International Journal of Climatology, 28 (3), 329–342.
  13. ^Patrick Laux et al. (2009): Modelling daily precipitation features in the Volta Basin of West Africa. International Journal of Climatology, 29 (7), 937–954.,
  14. ^David Vandervort (2009).Darfur: getting ready for the rainy season.International Committee of the Red Cross. Retrieved on 2009-02-06.
  15. ^Mehari Tesfazgi Mebrhatu, M. Tsubo, and Sue Walker (2004).A Statistical Model for Seasonal Rainfall Forecasting over the Highlands of Eritrea.New directions for a diverse planet: Proceedings of the 4th International Crop Science Congress. Retrieved on 2009-02-08.
  16. ^Alex Wynter (2009).Ethiopia: March rainy season "critical" for southern pastoralists.Thomson Reuters Foundation. Retrieved on 2009-02-06.
  17. ^The Voice (2009).Botswana: Rainy Season Fills Up Dams.allAfrica.com. Retrieved on 2009-02-06.
  18. ^Randy Lascody (2008).The Florida Rain Machine.National Weather Service.Retrieved on 2009-02-06.
  19. ^OCHA Partnership for Humanity (2008).OCHA Field Situation Report: Indonesia – Rainy Season 1 December 2008.Archived18 February 2009 at theWayback MachineUnited Nations Office for the Coordination of Humanitarian Affairs. Retrieved on 2009-02-06.
  20. ^Burarra Gathering (2006).Burarra Gathering.Archived2012-03-20 at theWayback MachineBurarra Gathering. Retrieved on 2009-02-06.
  21. ^Tahiti Sun Travel Network (2007).About Bora Bora Island.Retrieved on 2009-02-06.
  22. ^Joint Typhoon Warning Center(2006).2.4 Analysis & Forecasting "Thumb Rules" for the Rainy Season.United States Navy.Retrieved on 2009-02-06.
  23. ^Remote Sensing for Migratory Creatures (2002).Phenology and Creature Migration: Dry season and wet season in West Mexico.Arizona Remote Sensing Center. Retrieved on 2009-02-06.
  24. ^J. Horel (2006).Normal Monthly Precipitation, Inches.Archived2006-11-13 at theWayback MachineUniversity of Utah. Retrieved on 2008-03-19.
  25. ^abHorace Burton (2006).The climate of Guyana.Archived2009-01-24 at theWayback MachineCaribbean Institute for Meteorology and Hydrology. The Outfield, August 2006, pp. 3. Retrieved on 2009-02-08.
  26. ^abJames Brian Elsner (1988).Analysis of Wet Season Rainfall Over the Nordeste of Brazil, South America.University Of Wisconsin-Milwaukee. Retrieved on 2009-02-06.
  27. ^C. H. Mari, G. Cailley, L. Corre, M. Saunois, J. L. Attie, V. Thouret, and A. Stohl (2007).Biomass burning plumes during the AMMA wet season experiment.Atmospheric Chemistry and Physics Discussions, pp. 17342. Retrieved on 2009-02-06.
  28. ^Greek Embassy London (2008).Welcome to Greece.Archived2012-02-20 at theWayback MachineGovernment of Greece. Retrieved on 2009-02-06.
  29. ^D. Bozkurt, O.L. Sen and M. Karaca (2008).Wet season evaluation of RegCM3 performance for Eastern Mediterranean.EGU General Assembly. Retrieved on 2009-02-06.
  30. ^Kahana, Ron; Ziv, Baruch; Enzel, Yehouda & Dayan, Uri (2002)."Synoptic Climatology of Major Floods in the Negev Desert, Israel"(PDF).International Journal of Climatology.22(7): 869.Bibcode:2002IJCli..22..867K.doi:10.1002/joc.766.S2CID129438767.Archived fromthe original(PDF)on 2011-07-19.
  31. ^Michael J. Plagens (2009).What and Where is the Sonoran Desert?Arizonensis. Retrieved on 2009-02-07.
  32. ^"The Six Seasons".Australian Government, Department of the Environment.RetrievedApril 25,2016.
  33. ^Official Web Site of District Sirsa, India (2001).District Sirsa.Archived2010-12-28 at theWayback MachineNational Informatice Center. Retrieved on 2008-12-27.
  34. ^Mei Zheng (2000).The sources and characteristics of atmospheric particulates during the wet and dry seasons in Hong Kong.Archived2012-01-08 at theWayback MachineUniversity of Rhode Island. Retrieved on 2008-12-27.
  35. ^S. I. Efe, F. E. Ogban, M. J. Horsfall, E. E. Akporhonor (2005).Seasonal Variations of Physico-chemical Characteristics in Water Resources Quality in Western Niger Delta Region, Nigeria.Journal of Applied Scientific Environmental Management. Retrieved on 2008-12-27.
  36. ^C. D. Haynes, M. G. Ridpath, M. A. J. Williams (1991).Monsoonal Australia.Taylor & Francis, pp. 90.ISBN978-90-6191-638-3.Retrieved on 2008-12-27.
  37. ^abUnited States War Department (1909).Road Notes, Cuba. 1909.United States Department of War. Retrieved on 2009-01-16.
  38. ^K.W. Choi and J.H.W. Lee (2000).Wet Season Tidal Circulation and flushing in Three Fathoms Cove.Archived2009-02-27 at theWayback Machine4th International Conference on Hydro-Science and Engineering. Retrieved on 2008-12-27.
  39. ^Overseas Security Advisory Council (2009).Warden Message: Guyana Rainy Season Flood Hazards.[permanent dead link]Overseas Security Advisory Council. Retrieved on 2009-02-05.
  40. ^National Flood Insurance Program (2009).California's Rainy Season.Archived2012-12-04 at theWayback MachineFederal Emergency Management Agency.Retrieved on 2009-02-05.
  41. ^AFP (2009).Bali Hit By Wet Season Floods.ABC News.Retrieved on 2009-02-06.
  42. ^"Sirsa District Disaster Management Plan, 2015-2016"(PDF).District Sirsa.Government of Haryana Department of Revenue and Disaster Management, Haryana Institute of Public Administration. 2015. Archived fromthe original(PDF)on 2016-03-28.RetrievedApril 25,2016.
  43. ^Jack Ainsworth & Troy Alan Doss.Natural History of Fire & Flood Cycles.California Coastal Commission. Retrieved on 2009-02-05.
  44. ^FESA (2007).Flood.Archived2009-05-31 at theWayback MachineGovernment of Western Australia. Retrieved on 2009-02-06.
  45. ^King County Department of Development and Environmental Services (2009).Erosion and Sediment Control for Construction Sites.King County, Washington Government. Retrieved on 2009-02-06.
  46. ^Charles Darwin University(2009).Characteristics of tropical savannas.Archived2009-02-17 at theWayback MachineCharles Darwin University. Retrieved on 2008-12-27.
  47. ^Frisancho, A. Roberto (1993).Human Adaptation and Accommodation.University of Michigan Press.ISBN978-0-472-09511-7.
  48. ^Marti J. Van Liere, Eric-Alain D. Ategbo, Jan Hoorweg, Adel P. Den Hartog, and Joseph G. A. J. Hautvast. The significance of socio-economic characteristics for adult seasonal body-weight fluctuations: a study in north-western Benin. British Journal of Nutrition: Cambridge University Press, 1994.
  49. ^African Centre of Meteorological Application for Development (2008).Ten Day Climate Bulletin: Dekad of 01 to 10 April, 2008.Archived2009-02-27 at theWayback MachineACMAD. Retrieved on 2009-02-08.
  50. ^John P. McNamara, J. France, D. E. Beever (2000).Modelling Nutrient Utilization in Farm Animals.CABI, pp. 275.ISBN978-0-85199-449-9.Retrieved on 2009-02-06.
  51. ^Lincoln Brower(2005).Precipitation at the Monarch Overwintering Sites in Mexico.Archived2012-10-06 at theWayback MachineJourney North. Retrieved on 2009-02-06.
  52. ^Paul M. Brakefield and Torben B. Larsen (1983).The evolutionary significance of dry and wet season forms in some tropical butterflies.Biological Journal of the Linnean Society,pp. 1–12. Retrieved on 2008-12-27.
  53. ^Phil Hall (1989).Crocodiles, Their Ecology, Management, and Conservation.International Union for Conservation of Nature and Natural Resources Crocodile Specialist Group, pp. 167. Retrieved on 2008-12-27.
  54. ^San Diego Natural History Museum (2009).Bufo californicus: Arroyo Toad.San Diego Natural History Museum. Retrieved on 2009-01-16.
  55. ^Linda Deuver (1978).Dry season, wet season.Archived2009-01-20 at theWayback MachineAudubon Magazine, November 1978, pp. 120–130. Retrieved on 2009-02-06.
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