+----------+---------+---------+---------+---------+
| Station. | Winter. | Spring. | Summer. | Autumn. |
+----------+---------+---------+---------+---------+
|Ouargla | 37 | 39 | 4 | 20 |
|Laghouat | 11 | 27 | 31 | 31 |
|Ghardaia | 15 | 23 | 13 | 49 |
|Touggourt | 13 | 30 | 3 | 53 |
+----------+---------+---------+---------+---------+
The relative humidity at the desert stations is often very low,
sometimes running in midsummer between 7 and 9 per cent for 6 days,
and occasionally being too low to measure with the instruments
employed. The mean relative humidity (table 4) shows the general
very dry condition of the air of the desert as contrasted with a
station in the Tell, and also indicates something of the monthly
variations in this factor experienced among the desert stations
themselves. The averages given are from 4 to 8 years, except the
mean annual for In Salah, which is for 2 years only.