Weather Data Shift to Open Access Works for ECMWF

Why this is here: Following the transition, more than 93% of organizations previously paying for ECMWF’s weather data continued service agreements, indicating strong retention despite open access.

Researchers at the European Centre for Medium-Range Weather Forecasts (ECMWF) in the United Kingdom found a shift to open access data is sustainable. ECMWF moved from requiring licenses for its weather data to offering it freely under an open license, completing this change in October 2025. This decision followed EU policies promoting open data sharing and international data exchange agreements.

ECMWF used a tiered system. Core forecast data became openly available.

Supported delivery services, ensuring reliable access, remained available for a fee. From 2020 to 2025, the center planned the transition yearly, setting revenue reduction targets and expanding the open data offerings.

After six months, over 93% of organizations that previously paid for data continued with service agreements. Downloads of open data greatly increased.

A challenge exists with freely available AI forecasts. Longer-term monitoring of service contracts will be needed to confirm this approach remains sustainable.