To take early action before a potential disaster, humanitarians continually request several weeks of preparation time. This is currently outside the realm of traditional weather forecasts, and sub-seasonal to seasonal (S2S) forecasts are poised to meet this demand. This chapter provides a case study of a pilot project in Peru that used S2S forecasts to prepare for extreme rainfall, in conjunction with seasonal and weather forecasts. The forecast triggered action in vain at that time, but it also provided a window into the planning and skill needs of the humanitarian sector. A key recommendation is to provide skill estimates for operational S2S forecasts so that disaster managers can evaluate the type of action that would be merited based on the forecast information.