The Southern Hemisphere is the half sphere of Earth which is south of the equator. It contains all or parts of five continents[1] (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. Due 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.