The climate of the Saharan provinces is primarily characterized by a very low amount of precipitation. The absence of significant reliefs, the direction parallel to the coast of trade winds and the stability of the atmospheric circulation prevent a rainfall increase in the region.
The southern region receives a lower amount of precipitation: the overall amount of rainfall is estimated at 11 mm of rain/year, whereas in Laâyoune it reaches 40 mm. Nevertheless, the recent years have witnessed more frequent precipitations, which have given life to soil and hope to farmers and stockbreeders who have extended their activities.
The influence of the ocean is well seen in the relative atmosphere humidity. Fog and smog are frequent: Tarfaya, 24 dew days per year, 33 in Dakhla and 2 only in Smara.
Humidity directly influences temperatures. As we move away from coasts, the annual thermal amplitude increases: it is 16° on the coast and on 24 ° in Smara. At sea edge, temperatures vary between an average 12° in January and an average 28° in July; inwards, between 6 and 8° and 32°. Consequently, the Moroccan Sahara is bordered by an attenuated desert.