In the Sahel of West Africa, food security is a top development priority. Climate shocks threaten communities that rely on a single rainy season to grow crops and raise livestock. We exploit repeat surveys collected by the World Food Programme to quantitatively assess the year-to-year dynamics of household food security. Our methodology singles out the impact of climate shock on food access. We combine three variables, namely the Food Consumption Score, the Food Expenditure Share and the Reduced Coping Strategies Index to explore the access dimension of food security. Cluster analysis on the three variables leads us to 1) classify into categories, and spatially locate less and more food secure households; and 2) discuss the response of each category of household to seasonality and variability in climate. First, we find that in a drought year, some rural householdswith average food security statusthat normally do not use coping strategies actually have to use them. Second, we notice that food expenditure share increases in all categories of households, except one. Based on the different ways in which categories of households respond to (climatic) shock we recommend the design of targeted and more efficient interventions. We focus on Senegal because of the unprecedented opportunity to access repeat surveys, including an unusual one, taken during a crisis year. However, our methodology and recommendations can inform interventions in other Sahelian countries.