World's largest hot desert. Located in north Africa and covers over 3,500,000 square miles (9,000,000 sq km) or roughly 10% of the continent. Mean temperature over 30 degrees C. Variations may also be huge, from over 50 degrees C during the day, to temperatures below 0 at night in summer.
Fall begins (Northern H.) History. Fall begins in the Northern Hemisphere when the Sun is perpendicular to the equator. This day has equal hours of day and night. The first day of Fall is also called the Autumnal Equinox. In many areas it coincides with harvests. The first day of Fall happens between each year between September 22 and 24.
How do clouds make rain? Quick Answer. Precipitation occurs when moist air rises to cooler altitudes, condensing the water out of the air into droplets. Once these droplets become heavy enough, often by coalescing around motes of dust or other particles, they fall out of the cloud as precipitation. Without significant updrafts bringing more moisture to the cloud layer, the condensed water may remain light enough to stay aloft, which is why not every cloud brings rain.