 The hivernage begins earlier in the Sahelian Zone than in the Saharan Zone, often lasting from June until October.Because farmers and herders depend on annual rains, a delay of one month in the beginning of the rainy season can cause large losses and lead to mass migrations from Hodh ech Chargui and Hodh el Gharbi into Mali.Although temperature extremes are narrower than in the Saharan Zone, daily variations range from .