+-------+-----+------------+-------+------+-----------------------+ | |Tell | High |Saharan|Desert| | |Season.|(10).|Plateau (8).| Atlas | (6).| Remarks. | | | | | (10). | | | +-------+-----+------------+-------+------+-----------------------+ | |_mm._| _mm._ | _mm._ | _mm._| | | | | | | | | |Winter |469.9|119.3 (50.8)| 113.5| 37.4| The Tell is | | | | | | | represented by Fort | |Spring |300.0| 80.5 (95.0)| 88.2| 39.0| National; the High | | | | | | | Plateau by Geryville | |Summer | 38.1| 66.5 (35.8)| 50.4| 3.7| (with Ain Sefra, | | | | | | | for 6 years, in | |Autumn |287.2|139.5 (58.5)| 123.1| 19.6| parentheses); the | | | | | | | Saharan Atlas by | | | | | | | Djelfa; the desert by | | | | | | | Ouargla. The number | | | | | | | of yearly records on | | | | | | | which averages are | | | | | | | computed are given | | | | | | | at the head of each | | | | | | | column in parentheses.| +-------+-----+------------+-------+------+-----------------------+ The seasonal percentages of precipitation give a more graphic conception of the rainfall conditions for the four physiographic provinces. In the Tell this percentage in winter is 42, in spring 27, in summer 4, and in autumn 27. On the High Plateau the percentages are 30, 20, 16, and 34 for the four seasons respectively. In the Saharan Atlas 30 per cent of the rain occurs in winter, 24 in spring, 13 in summer, and 33 in autumn. In the desert the percentages of rainfall are 37, 39, 4, and 20[3] for the four seasons. It is of interest also to note the number of days on which the rain fell on an average each year over a period running from 7 to 12 years. Thus at two typical stations on the Tell rain was reported on 102 and 118 days; at two stations on the High Plateau it rained 65 and 83.8 days; at a station in the Saharan Atlas rain was reported on 70 days; at desert stations, at Ouargla rain fell on an average 14.2, and at Laghouat 49 days each year. As a comparison, it may be mentioned that for ten years at Wady Halfi, Egyptian Sudan, there were only 22 days on which rain-drops were seen to fall. (Engler, _loc. cit._)