text: Its southern part includes a significant portion of the Sahara.To the north, the Tell Atlas form with the Saharan Atlas, further south, two parallel sets of reliefs in approaching eastbound, and between which are inserted vast plains and highlands.Both Atlas tend to merge in eastern Algeria.The vast mountain ranges of Aures and Nememcha occupy the entire northeastern Algeria and are delineated by the Tunisian border.The highest point is Mount Tahat ().Algeria lies mostly between latitudes 19° and 37°N (a small area is north of 37°N and south of 19°N), and longitudes 9°W and 12°E.Most of the coastal area is hilly, sometimes even mountainous, and there are a few natural harbours.The area from the coast to the Tell Atlas is fertile.South of the Tell Atlas is a steppe landscape ending with the Saharan Atlas; farther south, there is the Sahara desert.The Hoggar Mountains (), also known as the Hoggar, are a highland region in central Sahara, southern Algeria.They are located about south of the capital, Algiers, and just east of Tamanghasset.Algiers, Oran, Constantine, and Annaba are Algeria's main cities.Climate and hydrology In this region, midday desert temperatures can be hot year round.After sunset, however, the clear, dry air permits rapid loss of heat, and the nights are cool to chilly.Enormous daily ranges in temperature are recorded.Rainfall is fairly plentiful along the coastal part of the Tell Atlas, ranging from annually, the amount of precipitation increasing from west to east.Precipitation is heaviest in the northern part of eastern Algeria, where it reaches as much as in some years.Farther inland, the rainfall is less plentiful.Algeria also has ergs, or sand dunes, between mountains.Among these, in the summer time when winds are heavy and gusty, temperatures can go up to .Fauna and flora The varied vegetation of Algeria includes coastal, mountainous and grassy desert-like regions which all support a wide range of wildlife.