The Earth's Northern and Southern Hemispheres are divided by the equator, which is an imaginary line located at 0 degrees latitude. The Northern Hemisphere consists of most of Asia, northern South America, Europe, North America and two-thirds of Africa's landmass. The Earth's Southern Hemisphere is comprised of Antarctica, one-third of Africa, Australia, a small number of Asian islands and much of South America.
Climates differ between the Northern and Southern Hemispheres, which is due to the Earth's seasonal slant toward and away from the sun. Summer months in the Northern Hemisphere begin in June and continue through September, while summer in the Southern Hemisphere starts in December and ends before March is over.