In a groundbreaking commitment that is set to redefine the accessibility and utilization of meteorological data worldwide, the European Centre for Medium-Range Weather Forecasts (ECMWF) has announced a bold strategy to make its vast and invaluable datasets openly accessible. This move, which accelerates the centre’s original timeline, will see the full ECMWF real-time forecast catalogue released under a Creative Commons Attribution 4.0 (CC-BY-4.0) license by the end of 2025. The initiative is poised to transform the landscape of global weather forecasting, enhancing societal resilience and enabling broader and faster scientific innovation.
ECMWF, an intergovernmental organisation renowned for its cutting-edge numerical weather predictions, houses one of the largest meteorological archives globally, amassing over 1.3 exabytes of data. This extensive repository encompasses historical climate records and real-time forecast products generated through sophisticated modeling systems like the Integrated Forecast System (IFS) and the AI-driven AIFS. As part of its strategic vision for 2025-2034, ECMWF is actively dismantling access barriers, broadening the utility of its data to support initiatives such as the United Nations’ Early Warnings for All campaign, which seeks to democratize access to life-saving meteorological information.
The transition to open data access is meticulously engineered to follow FAIR principles — ensuring data is Findable, Accessible, Interoperable, and Reusable. Since 2019, ECMWF’s collaborative efforts with its 23 Member States and 12 Co-operating States have focused on equitable data dissemination. By eliminating information or data access charges and only applying delivery fees where necessary, ECMWF democratizes its product offering while sustaining the infrastructural costs associated with data transfer and processing. This approach recognises the complex and voluminous nature of meteorological datasets, which includes 100 terabytes of freshly-generated data daily spanning over 450 critical atmospheric parameters.
ECMWF’s decision to implement a “no latency – no delay” model for open forecast data at a 25-kilometer resolution from October onwards marks a significant leap. Notably, the organisation plans to escalate the detail of these forecasts to the native 9-kilometer resolution within a two-hour latency window, balancing the heightened computational and delivery demands of enhanced spatial granularity with operational feasibility and cost management. This ensures real-time applications, such as disaster risk management and climate impact assessments, can leverage cutting-edge forecasts without prohibitive delays or resource constraints.
Beyond the raw data, ECMWF facilitates user accessibility and usability through enhanced interfacing and tooling. A suite of more than 400 pre-made meteorological charts, shared under the CC-BY-4.0 licence, enables rapid visualization without requiring advanced technical skills. Additionally, ECMWF supports open-source tools and example Jupyter Notebooks that illustrate data handling and interpretation workflows, catering to users ranging from beginners to experts. This broader ecosystem supports not only academic research but also operational meteorology and machine learning applications.
To accommodate varied user needs and integration scenarios, ECMWF offers data in multiple formats, including via web interfaces and APIs. This flexibility allows seamless ingestion of data into diverse modeling environments, weather apps, and decision-support systems globally. Such adaptability is critical as meteorological applications increasingly intersect with AI, IoT, and smart infrastructure, requiring real-time, high-resolution, and interoperable data streams.
Significantly, ECMWF highlights the importance of attribution under its CC-BY-4.0 open data license, a legal imperative that benefits both the data users and ECMWF itself. Proper attribution ensures transparency, supports ongoing public investment in high-quality forecasting, and enables ECMWF to track and celebrate innovative uses of its data. This mutual reinforcement underscores an ethical and strategic dimension to open science, emphasizing trustworthiness and sustained collaboration.
ECMWF’s robust governance structure, backed by 35 Member and Co-operating States, underpins this open data transition. These nations continuously co-invest in ECMWF’s high-performance computing infrastructure, including recently upgraded GPU clusters essential for AI and machine learning workloads. Initiatives like the European Weather Cloud exemplify ECMWF’s push toward creating integrated, scalable platforms that facilitate data-driven innovation and operational forecasting improvements.
The availability of open data is already yielding tangible benefits across multiple domains. Public good and societal benefit activities such as early warning systems, humanitarian aid, and climate research are prioritized, often through financial access waivers and dedicated support mechanisms. For instance, National Meteorological and Hydrological Services (NMHS) affiliated with the World Meteorological Organization and supported by the UN’s Systematic Observations Financing Facility (SOFF) gain preferential access to high-resolution datasets critical for their mandates.
As ECMWF progressively opens its data to the public, the centre maintains a commitment to excellence and reliability. Forecast products are generated at 0.25-degree resolution in the GRIB2 format, now enhanced with CCSDS compression for more efficient transmission. The IFS forecast data become publicly available one hour after dissemination, while the AIFS products are released immediately after production, offering users rapid access to the latest predictive insights.
To conclude, ECMWF’s open data policy represents a paradigm shift in meteorology, driven by a vision of transparency, equity, and technological advancement. By breaking down barriers to data accessibility and investing in user-centric tools and infrastructure, ECMWF empowers a global community of scientists, decision-makers, and citizens to better anticipate weather phenomena, mitigate risks, and adapt to climate change. This strategic openness not only democratizes information but fosters a more resilient and informed society worldwide.
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Subject of Research: Not applicable
Article Title: ECMWF Accelerates Open Data Access: A New Era for Global Weather Forecasting
News Publication Date: Not specified
Web References:
– https://www.ecmwf.int/en/forecasts/datasets/open-data
– https://www.ecmwf.int/sites/default/files/elibrary/2025/81641-ecmwf-strategy-2025-2034.pdf
– https://creativecommons.org/licenses/by/4.0/
References: Not specified
Image Credits: ECMWF
Keywords: Atmospheric science, numerical weather prediction, open data, meteorology, climate forecasting, ECMWF, Creative Commons, FAIR data, high-performance computing
