What is the biggest desert in the world?
Antarctica is the largest desert on Earth and is nearly twice the size of Australia.
Deserts are defined by how little rain or snow they get, not by how hot they are. Antarctica is the driest continent because its interior receives less than 2 inches of water per year. Most of the snow that falls there never melts and turns into thick ice over millions of years.
Nerd's Section
Scientists define a desert as any area that receives less than 10 inches of precipitation per year. Antarctica covers about 5.5 million square miles. The Sahara Desert in Africa is much smaller at about 3.6 million square miles. Some parts of Antarctica called the McMurdo Dry Valleys have not seen rain or snow for 2 million years.The air in Antarctica is too cold to hold much water vapor. This creates extremely low humidity across the continent. Data from the National Snow and Ice Data Center shows that Antarctica holds 70% of the world's fresh water as ice. However, it is still a polar desert because new water rarely falls from the sky.Gravity pulls cold, heavy air down from the high center of the continent. These are called katabatic winds and can reach 200 miles per hour. These winds dry out the land even more. The dry air is helpful for scientists at the Amundsen-Scott South Pole Station. The lack of water vapor in the air makes it easier for telescopes to see clearly into space.
Verified Fact
FP-0002788 · Mar 24, 2026