Tropical Climates (A)
Sunday, July 5, 2026 7:38 AM
Köppen Climatic Types:
- Tropical Climates (A)
○ Approx. 36% of the earth's surface (land & water areas) are located in the tropics
(between the Tropics of Cancer & Capricorn). About 1/3 of the world's people live
in the tropics, these latitudes mark boundaries of the area where the sun is directly
overhead at least one day each year. The tropical, low latitudes, are hot & humid
most of the year & are dominated by warm tropical air. According to Köppen, to be
classified as a tropical climate, the temperature of the coolest month must be
warmer than 64 degrees F & must average 70-80 degrees F.
○ While the temperature patterns are consistent in the tropics, precipitation has
greater variability. Several factors cause precipitation in the tropics:
§ convection, convergence of trade winds & orographic effects. There are 3
subtypes of tropical climates due to variations in precipitation patterns within
this region.
a. Tropical Wet/Tropical Rainforest (Af)
- This is a climate w/ high temps & heavy precipitation in all months of the year (no dry
season). This climate is described as being “monotonous” b/c of the lack of variation in
the weather year-round
- Location
○ The tropical wet climate is the most equator-ward of all climate types. Straddling the
equator up to 10 degrees on either side, three large land areas are contained within
the tropical wet climate: Amazon basin in South America, the Congo basin in West
Africa & the majority of the islands of the East Indies.
- Temperature
○ The range in temps between day & night is greater than the range in temp from the
coldest to warmest month of the year. It‘s said that night is considered to be winter
of the tropics, this is b/c the diurnal (day to night) temps range is greater than the
annual (seasonal) range. The constantly high midday sun angles & consistent daylight
lengths (about 12hrs) all year. Only the rhythm of day & night provide thermal
variety, for example, the average daytime temp is about 80F during the day & the
nighttime temp about 70F at night, while the average monthly temp around 75F all
year
- Precipitation
○ Humidity is high b/c of warm annual temps & high rates of evaporation. This is the
world's rainiest climate type w/ rainfall 1-3x a day & around 60-100 inches/yr. The
region is dominated by maritime tropical (mT), warm & humid air masses which yield
heavy rainfall. Two factors are responsible for high rates of precipitation: intense
surface heating from the direct sun received year-round in the tropics, creates
convectional precipitation. This region has a distinct afternoon precipitation pattern
& often afternoon thunderstorms. When air hits a mountain or volcano in this region,
orographic clouds form along windward locations of these high mountain barriers (as
in Hawaii).
B. Tropical Wet & Dry/Tropical Savannah
- This is the chief climate of the trade wind belts, one of the world's most important
climate types b/c it occupies an extensive & heavily populated area of the earth. It’s
called Tropical Savannah b/c of the savannah grasslands vegetation thriving in this wet
& dry climate
- Location
○ It‘s located between the ITCZ & the subtropical high. Its largest areas are in Latin
America & Africa, north of the tropical wet climate between 5-20 degrees or so N & S
of the equator.
- Temperature
○ The temperature pattern in the tropical wet & dry climate is the same as any tropical
climate. The monthly averages in temperature are all above 64 degrees F, with little
change in temperature (if any) from season to season. The greatest change in
temperature in the tropics happens diurnally (from day to night)
- Precipitation (START WRITING FROM HERE!!!)
○ The dominant control of the tropical wet & dry climate is the migration of the direct
ray from the sun (and its effects). This climate type is influenced by convection
during the high sun season, and subtropical high pressure (the trade winds bringing
dry air out of the high pressure belt) during the lower sun angle season (winter), as
the world's wind and pressure belts shift with the shifting of the vertical ray of the
sun
C. Tropical Monsoonal (Am)
- Location
○ This climate type is located along tropical coastlines, along west coasts. Some of the
major regions classifies as Am climates are Western India, West Africa, Australia, East
Asia, and Northern Brazil.
- Temperature
○ As mentioned w/ the other A climates, tropical climates have nearly the same
temperatures all year
- Precipitation
○ Very high precipitation occurs during the high sun season, when low pressure builds
above land & higher pressure under cooler oceans. Moisture blows in from the ocean
to the land & clouds develop. During the low sun season, offshore, dry winds prevail
b/c higher pressure builds over the land & lower pressure over the ocean. The cool
air blows over the land toward the ocean, creating drying conditions
Sunday, July 5, 2026 7:38 AM
Köppen Climatic Types:
- Tropical Climates (A)
○ Approx. 36% of the earth's surface (land & water areas) are located in the tropics
(between the Tropics of Cancer & Capricorn). About 1/3 of the world's people live
in the tropics, these latitudes mark boundaries of the area where the sun is directly
overhead at least one day each year. The tropical, low latitudes, are hot & humid
most of the year & are dominated by warm tropical air. According to Köppen, to be
classified as a tropical climate, the temperature of the coolest month must be
warmer than 64 degrees F & must average 70-80 degrees F.
○ While the temperature patterns are consistent in the tropics, precipitation has
greater variability. Several factors cause precipitation in the tropics:
§ convection, convergence of trade winds & orographic effects. There are 3
subtypes of tropical climates due to variations in precipitation patterns within
this region.
a. Tropical Wet/Tropical Rainforest (Af)
- This is a climate w/ high temps & heavy precipitation in all months of the year (no dry
season). This climate is described as being “monotonous” b/c of the lack of variation in
the weather year-round
- Location
○ The tropical wet climate is the most equator-ward of all climate types. Straddling the
equator up to 10 degrees on either side, three large land areas are contained within
the tropical wet climate: Amazon basin in South America, the Congo basin in West
Africa & the majority of the islands of the East Indies.
- Temperature
○ The range in temps between day & night is greater than the range in temp from the
coldest to warmest month of the year. It‘s said that night is considered to be winter
of the tropics, this is b/c the diurnal (day to night) temps range is greater than the
annual (seasonal) range. The constantly high midday sun angles & consistent daylight
lengths (about 12hrs) all year. Only the rhythm of day & night provide thermal
variety, for example, the average daytime temp is about 80F during the day & the
nighttime temp about 70F at night, while the average monthly temp around 75F all
year
- Precipitation
○ Humidity is high b/c of warm annual temps & high rates of evaporation. This is the
world's rainiest climate type w/ rainfall 1-3x a day & around 60-100 inches/yr. The
region is dominated by maritime tropical (mT), warm & humid air masses which yield
heavy rainfall. Two factors are responsible for high rates of precipitation: intense
surface heating from the direct sun received year-round in the tropics, creates
convectional precipitation. This region has a distinct afternoon precipitation pattern
& often afternoon thunderstorms. When air hits a mountain or volcano in this region,
orographic clouds form along windward locations of these high mountain barriers (as
in Hawaii).
B. Tropical Wet & Dry/Tropical Savannah
- This is the chief climate of the trade wind belts, one of the world's most important
climate types b/c it occupies an extensive & heavily populated area of the earth. It’s
called Tropical Savannah b/c of the savannah grasslands vegetation thriving in this wet
& dry climate
- Location
○ It‘s located between the ITCZ & the subtropical high. Its largest areas are in Latin
America & Africa, north of the tropical wet climate between 5-20 degrees or so N & S
of the equator.
- Temperature
○ The temperature pattern in the tropical wet & dry climate is the same as any tropical
climate. The monthly averages in temperature are all above 64 degrees F, with little
change in temperature (if any) from season to season. The greatest change in
temperature in the tropics happens diurnally (from day to night)
- Precipitation (START WRITING FROM HERE!!!)
○ The dominant control of the tropical wet & dry climate is the migration of the direct
ray from the sun (and its effects). This climate type is influenced by convection
during the high sun season, and subtropical high pressure (the trade winds bringing
dry air out of the high pressure belt) during the lower sun angle season (winter), as
the world's wind and pressure belts shift with the shifting of the vertical ray of the
sun
C. Tropical Monsoonal (Am)
- Location
○ This climate type is located along tropical coastlines, along west coasts. Some of the
major regions classifies as Am climates are Western India, West Africa, Australia, East
Asia, and Northern Brazil.
- Temperature
○ As mentioned w/ the other A climates, tropical climates have nearly the same
temperatures all year
- Precipitation
○ Very high precipitation occurs during the high sun season, when low pressure builds
above land & higher pressure under cooler oceans. Moisture blows in from the ocean
to the land & clouds develop. During the low sun season, offshore, dry winds prevail
b/c higher pressure builds over the land & lower pressure over the ocean. The cool
air blows over the land toward the ocean, creating drying conditions
