Table 9 gives the extreme daily range in temperature for three years observed at the stations named. TABLE 9.—_Absolute daily range in temperature._ +----------+-------+-------+-------+-------+-------+-------+ | Station. | Jan. | Feb. | Mar. | Apr. | May. | June. | +----------+-------+-------+-------+-------+-------+-------+ | | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | | In Salah | 21.6 | 23.0 | 24.4 | 24.6 | 22.0 | 23.2 | | Ouargla | 20.8 | 25.4 | 24.0 | 25.0 | 27.0 | 26.0 | +----------+-------+-------+-------+-------+-------+-------+ [**Continued] +----------+-------+-------+-------+-------+-------+-------+ | Station. | July. | Aug. | Sept. | Oct. | Nov. | Dec. | +----------+-------+-------+-------+-------+-------+-------+ | | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | | In Salah | 23.4 | 22.0 | 29.0 | 20.0 | 23.4 | 22.6 | | Ouargla | 26.0 | 27.8 | 24.6 | 23.0 | 20.0 | 23.8 | +----------+-------+-------+-------+-------+-------+-------+ A further examination of the maximum temperatures shows certain climatic features of interest and of great importance as factors in the environment of the desert plants, especially the high average maxima and the large amount of heat received in the desert, as indicated by a summation of the maximal temperatures. That the greatest daily temperatures must be high is indicated by table 10, which gives the average maxima for three to five years at three typical desert stations. TABLE 10.—_Average maximum temperatures._ +----------+-------+-------+-------+-------+-------+-------+ | Station. | Jan. | Feb. | Mar. | Apr. | May. | June. | +----------+-------+-------+-------+-------+-------+-------+ | | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | | Ouargla | 21.9 | 18.3 | 30.9 | 37.8 | 41.1 | 47.1 | | El Golea | 23.0 | 25.8 | 35.6 | 27.5 | 40.9 | 44.4 | | In Salah | 27.4 | 30.1 | 37.2 | 41.0 | 43.4 | 47.6 | +----------+-------+-------+-------+-------+-------+-------+ [**Continued] +----------+-------+-------+-------+-------+-------+-------+ | Station. | July. | Aug. | Sept. | Oct. | Nov. | Dec. | +----------+-------+-------+-------+-------+-------+-------+ | | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | _°C._ | | Ouargla | 49.4 | 47.7 | 44.3 | 40.0 | 31.0 | 25.0 | | El Golea | 47.5 | 46.0 | 43.8 | 36.7 | 29.9 | 22.4 | | In Salah | 44.3 | 47.1 | 45.9 | 41.3 | 37.0 | 27.1 | +----------+-------+-------+-------+-------+-------+-------+