Johannesburg (also known as Jozi, Jo'burg, eGoli, and Joeys, and abbreviated as JHB) is the largest city in South Africa. It is the provincial capital of Gauteng, which is the wealthiest province in South Africa. The city is one of the 50 largest urban agglomerations in the world, and is also the world's largest city not situated on a river, lake, or coastline. The city was named and established in 1886 following the discovery of gold on what had been a farm. The name is attributed to one or all of three men involved in the establishment of the city. In ten years, the population was 100,000 inhabitants.
While Johannesburg is not one of South Africa's three capital cities, it is the seat of the Constitutional Court, which has the final word on interpretation of South Africa's constitution as well as with issues in connection with constitutional matters. The city is the source of a large-scale gold and diamond trade, due to its location on the mineral-rich Witwatersrand range of hills.
In 2011, the population of the city of Johannesburg was 4,434,827, making it the largest city in South Africa. In the same year, the population of Greater Johannesburg Metropolitan Area was 7,860,781. Some view the area surrounding the city of Johannesburg yet more broadly than the Metropolitan Area, adding Ekurhuleni, West Rand and Lenasia; that larger area had a population of 10,267,700 in 2007. The land area of the municipal city, 1,645 km2 (635 sq mi), is large in comparison with those of other major cities, resulting in a moderate population density of 2,364/km2 (6,120/sq mi).
A separate city from the late 1970s until the 1990s, Soweto is now part of Johannesburg. Originally an acronym for "South-Western Townships", Soweto originated as a collection of settlements on the outskirts of Johannesburg, populated mostly by native African workers from the gold mining industry. Soweto, although eventually incorporated into Johannesburg, had been separated as a residential area for blacks, who were not permitted to live in Johannesburg proper. Lenasia is predominantly populated by English-speaking South Africans of Indian descent.
Johannesburg is located in the eastern plateau area of South Africa known as the Highveld, at an elevation of 5,751 feet (1,753 meters). The former CBD is located on the south side of the prominent ridge called the Witwatersrand (Afrikaans: White Water's Ridge) and the terrain falls to the north and south. By and large the Witwatersrand marks the watershed between the Limpopo and Vaal rivers as the northern part of the city is drained by the Jukskei River while the southern part of the city, including most of the CBD, is drained by the Klip River. The north and west of the city has undulating hills while the eastern parts are flatter.
Johannesburg may not be built on a river or harbour, but its streams contribute to two of southern Africa's mightiest rivers – the Limpopo and the Orange. Most of the springs from which many of these streams emanate are now covered in concrete and canalised, accounting for the fact that the names of early farms in the area often end with "fontein", meaning "spring" in Afrikaans. Braamfontein, Rietfontein, Zevenfontein, Doornfontein, Zandfontein and Randjesfontein are some examples. When the first white settlers reached the area that is now Johannesburg, they noticed the glistening rocks on the ridges, running with trickles of water, fed by the streams – giving the area its name, the Witwatersrand, "the ridge of white waters". Another explanation is that the whiteness comes from the quartzite rock, which has a particular sheen to it after rain.
Johannesburg is situated on the highveld plateau, and has a subtropical highland climate (Köppen Cwb). The city enjoys a sunny climate, with the summer months (October to April) characterized by hot days followed by afternoon thundershowers and cool evenings, and the winter months (May to September) by dry, sunny days followed by cold nights. Temperatures in Johannesburg are usually fairly mild due to the city's high elevation, with an average maximum daytime temperature in January of 25.6 °C (78.1 °F), dropping to an average maximum of around 16 °C (61 °F) in June. The UV index for Johannesburg in summers is extreme, often reaching 14-16 due to the high elevation and proximity to the equator.
Winter is the sunniest time of the year, with mild days and cool nights, dropping to 4.1 °C (39.4 °F) in June and July. The temperature occasionally drops to below freezing at night, causing frost. Snow is a rare occurrence, with snowfall having been experienced in the twentieth century during May 1956, August 1962, June 1964 and September 1981. In the 21st century, there has been light sleet in 2006, as well as snow proper on June 27th, 2007 (accumulating up to 4 inches (10.16 cm) in the southern suburbs) and August 7th, 2012.
Regular cold fronts pass over in winter bringing very cold southerly winds but usually clear skies. The annual average rainfall is 713 millimeters (28.1 in), which is mostly concentrated in the summer months. Infrequent showers occur through the course of the winter months. The lowest nighttime minimum temperature ever recorded in Johannesburg is −8.2 °C (17.2 °F), on 13 June 1979. The lowest daytime maximum temperature recorded is 1.5 °C (34.7 °F), on 19 June 1964.