The Southern Hemisphere is the half of Earth that is south of the Equator. It contains all or parts of five continents  ( Antarctica, Australia, about 90% of South America, the southern third of Africa, and several southern islands off the continental mainland of Asia), four oceans ( Indian, South Atlantic, Southern, and South Pacific) and most of the Pacific Islands in Oceania. Its surface is 80.9% water, compared with 60.7% water in the case of the Northern Hemisphere, and it contains 32.7% of Earth's land. 
Owing to the tilt of Earth's rotation relative to the Sun and the ecliptic plane, summer is from December to March and winter is from June to September. September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox. The South Pole is in the center of the southern hemispherical region.
Southern Hemisphere climates tend to be slightly milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic which is colder than the Arctic. This is because the Southern Hemisphere has significantly more ocean and much less land; water heats up and cools down more slowly than land.  The differences are also attributed to oceanic heat transfer (OHT) and differing extents of greenhouse trapping. 
In the Southern Hemisphere the sun passes from east to west through the north, although north of the Tropic of Capricorn the mean sun can be directly overhead or due south at midday. The Sun rotating through the north causes an apparent right-left trajectory through the sky unlike the left-right motion of the Sun when seen from the Northern Hemisphere as it passes through the southern sky. Sun-cast shadows turn anticlockwise throughout the day and sundials have the hours increasing in the anticlockwise direction. During solar eclipses viewed from a point to the south of the Tropic of Capricorn, the Moon moves from left to right on the disc of the Sun (see, for example, photos with timings of the solar eclipse of November 13, 2012), while viewed from a point to the north of the Tropic of Cancer (i.e., in the Northern Hemisphere), the Moon moves from right to left during solar eclipses.
The southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. This zone includes the southern tip of Uruguay and South Africa; the southern half of Chile and Argentina; parts of Australia, going south from Adelaide, and all of New Zealand.
The Sagittarius constellation that includes the galactic centre is a southern constellation and this, combined with clearer skies, makes for excellent viewing of the night sky from the Southern Hemisphere with brighter and more numerous stars.
Forests in the Southern Hemisphere have special features which set them apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique beech species or Nothofagus, and New Zealand has members of the closely related genera Lophozonia and Fuscospora. The eucalyptus is native to Australia but is now also planted in Southern Africa and Latin America for pulp production and, increasingly, biofuel uses.
Approximately 800 million humans live in the Southern Hemisphere, representing only 10–12% of the total global human population of 7.3 billion.   Of those 800 million people, 200 million live in Brazil, the largest country by land area in the Southern Hemisphere, while 141 million live on the island of Java, the most populous island in the world. The most populous nation in the Southern Hemisphere is Indonesia, with 261 million people (roughly 30 million of whom live north of the equator on the northern portions of the islands of Sumatra, Borneo and Sulawesi, while the rest of the population lives in the Southern Hemisphere). Portuguese is the most spoken language in the Southern Hemisphere,  followed by Spanish and Javanese.
The largest metropolitan areas in the Southern Hemisphere are São Paulo (21 million people), Jakarta (18 million people), Buenos Aires (12 million people), Rio de Janeiro (11 million people), Kinshasa (11 million people) and Sydney (6 million) . The most important financial and commercial centers in the Southern Hemisphere are São Paulo, where the Bovespa Index is headquartered, along with Sydney, home to the Australian Securities Exchange, Johannesburg, home to the Johannesburg Stock Exchange and Buenos Aires, headquarters of the Buenos Aires Stock Exchange, the oldest stock market in the Southern Hemisphere.
Among the most developed nations in the Southern Hemisphere are Australia, with a nominal GDP per capita of US$51,850 and a Human Development Index of 0.939, the second highest in the world as of 2016. New Zealand is also well developed, with a nominal GDP per capita of US$38,385 and a Human Development Index of 0.915, putting it at #13 in the world in 2016. The least developed nations in the Southern Hemisphere cluster in Africa and Oceania, with Burundi and Mozambique at the lowest ends of the Human Development Index, at 0.404 (#184 in the world) and 0.418 (#181 in the world) respectively. The nominal GDP per capitas of these two countries don't go above US$550 per capita, a tiny fraction of the incomes enjoyed by Australians and New Zealanders.
The most widespread religions in the Southern Hemisphere are Christianity in South America, southern Africa and Australia/New Zealand, followed by Islam in most of the islands of Indonesia and in parts of southeastern Africa, and Hinduism, which is mostly concentrated on the island of Bali and neighboring islands.
The oldest continuously inhabited city in the Southern Hemisphere is Bogor, in western Java, which was founded in 669 CE. Ancient texts from the Hindu kingdoms prevalent in the area definitively record 669 CE as the year when Bogor was founded. However, there is some evidence that Zanzibar, an ancient port with around 200,000 inhabitants on the coast of Tanzania, may be older than Bogor. A Greco-Roman text written between 1 CE and 100 CE, the Periplus of the Erythraean Sea, mentioned the island of Menuthias ( Ancient Greek: Μενουθιάς) as a trading port on the east African coast, which is probably the small island of Unguja on which Zanzibar is located. The oldest proven archaeological site in the Southern Hemisphere is Sechin Bajo, located on the coast of northern Peru, and dates back to 3600 BCE. Sechin Bajo may also be the oldest site for monumental architecture in the Americas.
- Africa (about one-third, from south of Somalia in the east to south of Libreville in Gabon in the west)
- Antarctica (the entire continent and its associated islands are wholly within the Southern Hemisphere)
- Asia (the very southern island portion including East Timor, most of Indonesia, and a few islands (two out of the 26 atolls) of the Maldives)
- Australia (the entire mainland is in the Southern Hemisphere)
- South America (mostly, from south of the Amazon River mouth in the east to south of Quito in Ecuador in the west)
- Zealandia ( New Caledonia, New Zealand and other associated islands are wholly within the Southern Hemisphere)
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- Granite specific heat = 0.79 and water = 4.18 J/g⋅K see Heat capacity#Table_of_specific_heat_capacities.
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Media related to Southern Hemisphere at Wikimedia Commons