Introduction
A climate zone results from the climate conditions of an area: its temperature, humidity,
amount and type of precipitation, and the season. A climate zone is reflected in a region’s
natural vegetation. Perceptive travelers can figure out which climate zone they are in by
looking at the vegetation, even if the weather is unusual for the climate on that day!
Climate Zones and Biomes
The major factors that influence climate also determine the different climate zones. The
same type of climate zone will be found at similar latitudes and in similar positions on
nearly all continents, both in the Northern and Southern Hemispheres. The one exception
to this pattern is the climate zones called the continental climates, which are not found at
higher latitudes in the Southern Hemisphere. This is because the Southern Hemisphere land
masses are not wide enough to produce a continental climate.
Climate zones are classified by the Köppen classification system (Figure17.7). This sys-
tem is based on the temperature, the amount of precipitation and the times of year when
precipitation occurs. Since climate determines the type of vegetation that grows in an area,
vegetation is used as an indicator of climate type. A climate type and its plants and animals
make up abiome. The organisms of a particular biome share certain characteristics around
the world, because their environment has similar advantages and challenges. The organisms
have adapted to that environment in similar ways over time. For example, different species
of cactus live on different continents, but they have adapted to the harsh desert in similar
ways.
The Köppen classification system recognizes five major climate groups, each with a distinct
capital letter A through E. Each lettered group is divided into subcategories. Some of these
subcategories are forest (f), monsoon (m), and wet/dry (w) types, based on the amount of
precipitation and season when that precipitation occurs.
Tropical Moist Climates (Group A)
Tropical Moist(Group A) climates are found in a band about 15° to 25° N and S of the
equator (Figure17.8). Intense sunshine means that the tropics are warm year-round: each
month has an average temperature of at least 18°C (64°F). Rainfall is abundant — at least
150 cm (59 inches) per year. The subcategories of this zone are based on when the rain falls.
Tropical Wet (Af)
The wet tropics lie in a band around the equator, covering about 10% of the Earth’s land.
The wet tropics are consistently warm, with almost no annual temperature variation. Great