There are four main seasons around which pastoral and agricultural life revolve, and these are dictated by shifts in the wind patterns. From December to March is the ''Jilal'', the harshest dry season of the year. The main rainy season, referred to as the ''Gu'', lasts from April to June. This period is characterized by the southwest monsoons, which rejuvenate the pasture land, especially the central plateau, and briefly transform the desert into lush vegetation. From July to September is the second dry season, the ''Xagaa'' (pronounced "Hagaa"). The ''Dayr'', which is the shortest rainy season, lasts from October to December. The ''tangambili'' periods that intervene between the two monsoons (October–November and March–May) are hot and humid.