Dhaka Dhaka ( or ; bn, ঢাকা, Ḍhākā, ), formerly known as Dacca, is the capital and largest city of Bangladesh, as well as the world's largest Bengali-speaking city. It is the eighth largest and sixth most densely populated city ...

experiences a hot, wet and humid tropical climate. Under the

Köppen climate classification The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notabl ...

, Dhaka has a tropical wet and dry climate. The city has a distinct monsoonal season, with an annual average temperature of and monthly means varying between in January and in August. Nearly 80% of the annual average rainfall of occurs during the monsoon season which lasts from May until the end of September. Increasing air and water pollution emanating from traffic congestion and industrial waste are serious problems affecting public health and the quality of life in the city. Water bodies and

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

s around Dhaka are facing destruction as these are being filled up to construct multi-storied buildings and other real estate developments. Coupled with pollution, such erosion of natural habitats threatens to destroy much of the regional biodiversity. Cold weather is unusual in and around Dhaka. When temperatures decrease to or less, people without warm clothing and living in inadequate homes may die from the cold.

Factors

Dhaka has a tropical wet and dry climate. The

monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...

season brings nearly 80% of the annual average rainfall of 1,854 millimeters (73 in) occurs between May and September. *Southwest Monsoon occurs from June till September during the summer months. During this period very heavy rainfall lashes the city as well as the entire country. Flash floods are common in Dhaka almost every year. *Tropical Storms do occur during the summer months from April till June and then from September till December. These cyclones occur almost every year in Bangladesh though their intensity varies from year to year. *Tornadoes are fairly common in Bangladesh as it is one of the most frequently hit countries in the world, behind the United States and Canada.

Impact of climate change

Climate change has forced many people of

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

living in rural areas to migrate to cities that has caused a sharp rise in the slum population of Dhaka. As Bangladesh is already less than 20 feet above sea level, thus there are fears that by the end of the 21st century, more than a quarter of the country will be inundated and 15 million people will be displaced. The population of Dhaka, currently 13 million people, is projected to increase to 20 million by the year 2025. This raises fears of water-borne diseases and outbreaks of several other diseases. While a UN and WWF report warned that Dhaka tops the risk of climate change in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Monsoon rainfall of Dhaka

The

Monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...

season begins from June till September. The following is the annual monsoon rainfall for the last few years based on data from the Bangladesh Meteorological Department. *In 2000, a total of was recorded. *In 2001, a total of was recorded. *In 2002, a total of was recorded. *In 2003, a total of was recorded. *In 2004, a total of was recorded.
Baridhara DOHS during 2004 flood

*In 2005, a total of was recorded. *In 2006, a total of was recorded. *In 2007, a total of was recorded. *In 2008, a total of was recorded. *In 2009, a total of was recorded. *In 2010, a total of was recorded.

Extreme weather events

Extreme weather events include tropical cyclones,

tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...

es,

cloudburst A cloudburst is an extreme amount of precipitation in a short period of time, sometimes accompanied by hail and thunder, which is capable of creating flood conditions. Cloudbursts can quickly dump large amounts of water, e.g. 25 mm of prec ...

and

flash floods A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing o ...

. *In 1956, about 326 millimetres (12.8 in) of rain was recorded in 24 hours in Dhaka. *In 1970, a Category-3 tropical cyclone killed 500,000 people in the coastal area, which also had a severe impact in Dhaka. *In 1989, a

killed 1,300 people in

Dhaka Division Dhaka Division ( bn, ঢাকা বিভাগ, ''Ḑhaka Bibhag'') is an administrative division within Bangladesh. Dhaka serves as the capital city of the Dhaka Division, the Dhaka District and Bangladesh. The division remains a populati ...

. *In 1991, a Category-5 tropical cyclone ravaged coastal Bangladesh, impacting Dhaka with severe rain and damaging wind.http://www.swissre.com/resources/dd6346004d4e9669ac76eecedd316cf3-sigma2_2009_e.pdf *In 2004, a record-breaking 341 millimetres (13.4 in) mm of rain was recorded in Dhaka in 24 hours. *In 2009, about 333 millimetres (13.1 in) of rain was recorded in Dhaka in 24 hours.

Statistics

References

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Dhaka