The return of more abundant rainfall in the Sahel region since the early 2000s raises questions about the consequences of this change for breeders in the Ferlo region of Senegal. A detailed analysis of precipitation data shows that with the return of a more humid rainfall regime, the climatic risk has changed in nature but remains present. The increase in annual precipitations and in the lengthening of the rainy season is offset by an increase in rainfall aggressiveness and in the number of dry spells. In the end, the efficiency of precipitations in terms of vegetation growth does not increase or even decreases. The data collected in 2015 for a representative sample of farmers makes it possible to assess the impact of the monsoon characteristics on milk production and animal sales. The results, based on the analysis of livestock breeders' behavior in the dry and wet seasons, show the sensitivity of milk production to rainfall and vegetation conditions. They also show that adverse rainfall conditions lead farmers to increase livestock’s sales, but they do not support the income-smoothing hypothesis.