Antarctica is Earth's southernmost continent, overlying the South Pole. It is situated in the southern hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean and it is the fifth-largest continent in area after Eurasia, Africa, North America, and South America.On average, Antarctica is the coldest, driest and windiest continent, and has the highest average elevation of all the continents. Since there is little precipitation, except at the coasts, the interior of the continent is technically the largest desert in the world.

There are no permanent human residents. Only cold-adapted plants and animals survive there, including penguins, fur seals, mosses, lichen, and many types of algae. The climate of Antarctica does not allow extensive vegetation. A combination of freezing temperatures, poor soil quality, lack of moisture, and lack of sunlight inhibit the flourishing of plants. As a result, plant life is limited to mostly mosses and liverworts.  The flora of the continent largely consists of lichens, bryophytes, algae, and fungi. Growth generally occurs in the summer, and only for a few weeks at most.

Antarctica is the coldest place on Earth. At the 3-kilometer (2 mi)-high Vostok Station in Antarctica, scientists recorded Earth's lowest temperature: −89 °C (−129 °F). For comparison, this is 11 °C colder than subliming dry ice. Antarctica is a frozen desert with little precipitation; the South Pole itself receives less than 10 centimeters (4 in) per year, on average. Temperatures reach a minimum of between −80 °C and −90 °C (−112 °F and −130 °F) in the interior in winter and reach a maximum of between 5 °C and 15 °C (41 °F and 59 °F) near the coast in summer. Sunburn is often a health issue as the snow surface reflects almost all of the ultraviolet light falling on it.

Antarctica is divided in two by the Transantarctic Mountains close to the neck between the Ross Sea and the Weddell Sea. The portion west of the Weddell Sea and east of the Ross Sea is called Western Antarctica and the remainder Eastern Antarctica, because they roughly correspond to the Western and Eastern Hemispheres relative to the Greenwich meridian.About 98% of Antarctica is covered by the Antarctic ice sheet, a sheet of ice averaging at least 1.6 kilometers (1.0 mi) thick. The continent has about 90% of the world's ice (and thereby about 70% of the world's fresh water).

If all of this ice were melted, sea levels would rise about 60 meters (200 ft). In most of the interior of the continent, precipitation is very low, down to 20 millimeters (0.8 in) per year; in a few "blue ice" areas precipitation is lower than mass loss by sublimation and so the local mass balance is negative. In the dry valleys the same effect occurs over a rock base, leading to a desiccated landscape.