Tropical monsoon climate

Worldwide zones of Tropical monsoon climate (Am).

Tropical monsoon climate, occasionally also known as a tropical wet climate or tropical monsoon and trade-wind littoral climate in climate classification, is a relatively rare type of climate that corresponds to the Köppen climate classification category "Am."

Tropical monsoon climates have monthly mean temperatures above 18°C in every month of the year and feature wet and dry seasons, as Tropical savanna climates do. Unlike tropical savanna climates however, a tropical monsoon climate's driest month sees less than 60 mm of precipitation but more than (100 − [total annual precipitation {mm}/25]). Also a tropical monsoon climate tends to see less variance in temperatures during the course of the year than a tropical savanna climate. This climate has a driest month which nearly always occurs at or soon after the "winter" solstice for that side of the equator.

Versions

There are generally two versions of a tropical monsoon climate:

• The first version of the tropical monsoon climate features wet and dry seasons, with less pronounced dry seasons. Regions with this variation of the tropical monsoon climate typically sees copious amounts of rain during the wet season(s), usually in the form of frequent thunderstorms. However, unlike most tropical savanna climates, a sizeable amount of precipitation also falls during the dry season(s). In essence, this version of the tropical monsoon climate generally has less pronounced dry seasons than tropical savanna climates.
• The second version of the tropical monsoon climate features wet and dry seasons, with extraordinarily rainy wet seasons and pronounced dry seasons. This variation features pronounced dry seasons similar in length and character to dry seasons observed in tropical savanna climates. However, this is followed by a sustained period (or sustained periods) of extraordinary rainfall. In some instances, up to (and sometimes in excess of) 1,000 mm of precipitation is observed per month for two or more consecutive months. Tropical savanna climates generally do not see this level of sustained rainfall.

Distribution

Tropical monsoon climates are most commonly found in South and Central America. However, there are sections of South Asia, Southeast Asia, Africa (particularly West and Central Africa), the Caribbean, and North America that also features this climate.

Factors

The major controlling factor over a tropical monsoon climate is its relationship to the monsoon circulation. The monsoon is a seasonal change in wind direction. In Asia, during the summer (or high-sun season) there is an onshore flow of air (air moving from ocean towards land). In the “winter” (or low-sun season) an offshore air flow (air moving from land toward water) is prevalent. The change in direction is due to the difference in the way water and land heat.

Changing pressure patterns that affect the seasonality of precipitation also occur in Africa though it generally differs from the way it operates in Asia. During the high-sun season, the Intertropical convergence zone (ITCZ) induces rain. During the low-sun season, the subtropical high creates dry conditions. The monsoon climates of Africa, and the Americas for that matter, are typically located along tradewind coasts.

Notable Cities with Tropical Monsoon Climates

Miami, United States Nassau, Bahamas San Juan, Puerto Rico Santo Domingo, Dominican Republic Villahermosa, Mexico Belize City, Belize Macapá, Brazil Chittagong, Bangladesh Surat, India Thiruvananthapuram, India Mangalore, India Quezon City, Philippines Yangon, Burma

Jakarta, Indonesia Surakarta, Indonesia Alor Setar, Malaysia Phuket, Thailand Abidjan, Ivory Coast Port Harcourt, Nigeria Conakry, Guinea Freetown, Sierra Leone Monrovia, Liberia Douala, Cameroon Libreville, Gabon Kisangani, Democratic Republic of Congo Cairns, Australia

Charts of Selected cities

Miami
Climate chart (explanation)
J F M A M J J A S O N D     51   24 15     53   25 16     61   26 18     72   28 20     158   30 22     237   31 24     145   32 25     193   32 25     194   31 24     143   29 22     68   27 19     47   25 16 Average max. and min. temperatures in °C Precipitation totals in mm Source: WMO
Imperial conversion J F M A M J J A S O N D     2   75 59     2.1   76 60     2.4   79 64     2.9   82 68     6.2   85 72     9.3   88 75     5.7   89 76     7.6   89 77     7.6   88 76     5.6   85 72     2.7   80 67     1.8   77 62 Average max. and min. temperatures in °F Precipitation totals in inches

Medellin
Climate chart (explanation)
J F M A M J J A S O N D     55   27 17     77   27 16     114   27 16     179   28 16     191   28 16     153   28 16     108   28 16     154   28 16     178   27 16     218   27 16     150   27 17     79   27 17 Average max. and min. temperatures in °C Precipitation totals in mm Source: [2]
Imperial conversion J F M A M J J A S O N D     2.2   81 63     3   81 61     4.5   81 61     7   82 61     7.5   82 61     6   82 61     4.3   82 61     6.1   82 61     7   81 61     8.6   81 61     5.9   81 63     3.1   81 63 Average max. and min. temperatures in °F Precipitation totals in inches

Monrovia
Climate chart (explanation)
J F M A M J J A S O N D     31   30 23     56   29 23     97   31 23     216   31 23     516   30 22     973   27 23     986   27 22     373   27 23     744   27 22     772   28 22     236   29 23     130   30 23 Average max. and min. temperatures in °C Precipitation totals in mm Source: BBC [3]
Imperial conversion J F M A M J J A S O N D     1.2   86 73     2.2   84 73     3.8   88 73     8.5   88 73     20   86 72     38   81 73     39   81 72     15   81 73     29   81 72     30   82 72     9.3   84 73     5.1   86 73 Average max. and min. temperatures in °F Precipitation totals in inches

Chittagong
Climate chart (explanation)
J F M A M J J A S O N D     5   26 13     28   28 15     64   31 19     150   32 23     264   32 24     533   31 25     597   30 25     518   30 24     320   31 24     180   31 23     56   29 18     15   26 14 Average max. and min. temperatures in °C Precipitation totals in mm Source: BBC [4]
Imperial conversion J F M A M J J A S O N D     0.2   79 55     1.1   82 59     2.5   88 66     5.9   90 73     10   90 75     21   88 77     24   86 77     20   86 75     13   88 75     7.1   88 73     2.2   84 64     0.6   79 57 Average max. and min. temperatures in °F Precipitation totals in inches

Mangalore
Climate chart (explanation)
J F M A M J J A S O N D     0   31 21     0   31 22     0   32 24     30   32 25     150   35 26     940   28 24     980   27 23     590   27 23     260   28 23     200   30 23     70   31 23     10   31 22 Average max. and min. temperatures in °C Precipitation totals in mm Source: [5]
Imperial conversion J F M A M J J A S O N D     0   88 70     0   88 72     0   90 75     1.2   90 77     5.9   95 79     37   82 75     39   81 73     23   81 73     10   82 73     7.9   86 73     2.8   88 73     0.4   88 72 Average max. and min. temperatures in °F Precipitation totals in inches

Abidjan
Climate chart (explanation)
J F M A M J J A S O N D     41   31 23     53   32 24     99   32 24     125   32 24     361   31 24     495   29 23     213   28 23     53   28 22     71   28 23     168   29 23     201   31 23     79   31 23 Average max. and min. temperatures in °C Precipitation totals in mm Source: [6]
Imperial conversion J F M A M J J A S O N D     1.6   88 73     2.1   90 75     3.9   90 75     4.9   90 75     14   88 75     19   84 73     8.4   82 73     2.1   82 72     2.8   82 73     6.6   84 73     7.9   88 73     3.1   88 73 Average max. and min. temperatures in °F Precipitation totals in inches

Cairns
Climate chart (explanation)
J F M A M J J A S O N D     392   31 24     453   31 24     426   31 23     198   29 22     91   28 20     46   26 18     29   26 17     27   27 17     33   28 19     40   30 21     92   31 22     180   31 23 Average max. and min. temperatures in °C Precipitation totals in mm Source: [7]
Imperial conversion J F M A M J J A S O N D     15   89 75     18   88 75     17   87 73     7.8   85 71     3.6   82 68     1.8   79 64     1.2   78 63     1.1   80 63     1.3   82 66     1.6   85 69     3.6   87 72     7.1   89 74 Average max. and min. temperatures in °F Precipitation totals in inches

Thiruvananthapuram
Climate chart (explanation)
J F M A M J J A S O N D     23   32 22     24   32 23     40   33 24     117   33 25     230   32 25     321   30 24     227   29 23     138   29 23     175   30 23     282   30 23     185   30 23     66   31 23 Average max. and min. temperatures in °C Precipitation totals in mm Source: IMD
Imperial conversion J F M A M J J A S O N D     0.9   89 72     1   89 73     1.6   91 75     4.6   91 77     9.1   89 76     13   85 74     8.9   85 74     5.4   85 74     6.9   86 74     11   86 74     7.3   87 74     2.6   88 73 Average max. and min. temperatures in °F Precipitation totals in inches