In 2025, ECMWF marked its 50th anniversary, celebrating five decades of collaboration, innovation, and impact in numerical weather prediction and related sciences. The anniversary programme brought together scientists, technical experts, and users from our Member and Co-operating States across three event weeks in Bonn (Germany), Bologna (Italy), and Reading (UK), reflecting on ECMWF’s achievements and looking ahead to future advances.
The anniversary year opened in April with a week of events in Bonn, combining the Annual Seminar with four scientific workshops. Discussions spanned forecasting in a changing climate, advances in data assimilation, improved representation of surface–atmosphere interactions, and the growing importance of next-generation ancillary datasets. Machine learning featured prominently throughout, highlighting its increasing role alongside physics-based approaches. The breadth of participation and disciplines provided a snapshot of a field undergoing rapid transformation.
In September, the celebrations continued in Bologna, where more than 400 delegates took part in scientific and technical workshops. A central theme was high-performance computing (HPC) and its transformative role in weather and climate prediction. Delegates explored past achievements, current capabilities, and future directions, including the integration of artificial intelligence into forecasting systems and the development of digital twin technologies through the EU Destination Earth (DestinE) initiative.
The European Weather Cloud (EWC) User Workshop was also held in Bologna for the first time in person. Participants from academia, national meteorological services, and industry exchanged ideas and shared experiences on accessing and using ECMWF’s growing open datasets. The launch of the EWC Community Hub and the demonstration of new tools for data interaction highlighted ECMWF’s commitment to supporting a connected and collaborative research community.
The anniversary programme concluded in December in Reading, with events focused on machine learning for weather forecasting. These included a meeting of the Member State Machine Learning Pilot Project and a showcase of European capabilities, highlighting how machine learning is being integrated alongside physics-based models through close collaboration across ECMWF’s Member States. The celebrations were closed with a Gala evening that brought together Member States, partners, and current and former colleagues to mark the end of the 50th anniversary year.
Alongside the events, ECMWF celebrated the anniversary with the release of six publications highlighting key scientific and technical achievements in forecasting, data assimilation and high-performance computing. These were brought together in a commemorative book, 50 years of ECMWF, reflecting on the Centre’s history and its future role in the global meteorological community (available to download at https://www.ecmwf.int/en/elibrary/81684-50-years-ecmwf).
The 50th anniversary year was an opportunity to reflect on ECMWF’s journey – from its first operational forecasts in 1979 to today’s ensemble Earth-system approaches, machine learning applications and digital twin initiatives – and to thank the staff, partners and Member and Co-operating States who have shaped its success. The collaborations strengthened and insights shared during 2025 form a strong foundation for the next 50 years of advancing weather and environmental prediction.