Weather and climate services involve the production, translation, transfer, and use of scientific information for decision-making. They include long term climate projections, monthly to seasonal forecasts and daily weather forecasts. They are particularly useful (i) for several climate sensitive sectors such as agriculture, water resources, health, energy, disaster risk reduction and (ii) in developing countries where vulnerability to climate change and weather shocks is high. This interdisciplinary session aims at showing tools, results, methodologies that could lead in fine to an operational improvement of WCS in developing countries. It focuses not only on models improvement but also on how to interact with end-users, assess WCS added value, broadcast information, avoid inequalities access, involve the private sector etc. The session will focus particularly on feedbacks and results from different case studies located in the global South.