The rainfall, and hence the
tropical climateA tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures above...
is dominated by the
tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year, roughly following the
solar equatorThe solar equator is the latitude immediately "under" the sun; where the sun is vertically above at midday. Because of the inclination of the Earth's orbit the solar equator varies during the year, from the Tropic of Capricorn in December to the Tropic of Cancer in June....
; it is largely a manifestation of the ITCZ. The tropical rain belt lies in the southern hemisphere of the
Indian oceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
and western
Pacific oceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
roughly from October to March, and during this time the northern tropics experience a
dry seasonThe dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
in which precipitation is very rare, and days are typically hot and sunny throughout. From April to September, the rain belt lies in the northern hemisphere, and a
wet seasonThe the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
occurs there, while the southern tropics experience their dry season.
The rain belt reaches roughly as far north as the
Tropic of CancerThe Tropic of Cancer, also referred to as the Northern tropic, is the circle of latitude on the Earth that marks the most northerly position at which the Sun may appear directly overhead at its zenith...
and as far south as the
Tropic of CapricornThe Tropic of Capricorn, or Southern tropic, marks the most southerly latitude on the Earth at which the Sun can be directly overhead. This event occurs at the December solstice, when the southern hemisphere is tilted towards the Sun to its maximum extent.Tropic of Capricorn is one of the five...
in the western Pacific ocean. Its variation in the Western Hemisphere is minimal, roughly between the
equatorAn equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
and the
15th parallel northThe 15th parallel north is a circle of latitude that is 15 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, Central America, the Caribbean and the Atlantic Ocean....
latitude. Near these latitudes, there is one wet season and one dry season annually. On the equator, there are two wet and two dry seasons as the rain belt passes over twice a year, once moving north and once moving south. Between the tropics and the equator, locations may experience a short wet and a long wet season. Local geography may substantially modify these climate patterns, however.