Weather contributes both directly and indirectly to incidents, accidents, and delays in air traffic and hence derogates safety and efficiency of airport operations. Today, the aviation stakeholders receive their meteorological information from different sources, at different update rates and with different levels of resolution and accuracy, often leading to misunderstandings and even wrong decisions. The goal of the project is to develop a MEteorological Decision sUpport System for Aviation (MEDUSA) to provide adequate information about adverse weather situations to all decision makers in the airport environment such as airports, air navigation safety providers, airlines, and weather services. MEDUSA is a highly interdisciplinary and intersectorial project dedicated to the scientific and technological development of an end-user oriented application in the field of aviation meteorology including a marketing and commercialization strategy. MEDUSA, combining scientific complexity with high requirements on technical robustness, will provide an integrated weather information solution to aviation. Adverse summer weather like thunderstorms and heavy precipitation), and adverse winter weather situations like heavy snow fall, icing and freezing conditions at the airport will be considered. Key for the technical development is the integration of the various meteorological products in a robust, reliable, and real-time operational system with an easy-to-understand visualization to assist end-users in daily decision making. The project is organized in four phases, (i) test of existing algorithms and forecasting modules and selection of best suited algorithms and modules; (ii) development of joint platform MEDUSA; (iii) implementation and test of MEDUSA at the airports Munich, Frankfurt, and Barcelona including end-users’ feedback to improve the prototype; and (iv) dissemination of the results to the scientific and end-user communities and commercialization.