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.
Rating Newest Oldest. Best Answer: Officially, the third week of September when Fall starts all over the U.S at the autumnal equinox - this year it is September 22nd. And you can find this answer easily through many other methods, like simply googling when does fall start.. You'd be surprised how google search can answer questions.