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Milestone in Climate and Weather Research

Press Release01 February 2024

The scientific and research community in Germany and Switzerland is setting a milestone in climate and weather research: Since 31 January, 2024, the renowned climate and weather model ICON has been made available to the public under an open source license. This step will open up the scientific basis for weather forecasts and climate projections and make it available to everyone.

  • Measurement & forecasting systems
  • Weather
  • Climate


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The ICON Model System

The institutions behind ICON (ICOsahedral Non-hydrostatic modeling framework) and its current developers are the German Climate Computing Center (DKRZ), the German Meteorological Service (DWD), the Karlsruhe Institute of Technology (KIT), the Max Planck Institute for Meteorology (MPI-M), and the Swiss Center for Climate Systems Modeling (Federal Office of Meteorology and Climatology MeteoSwiss and ETH Zurich as C2SM partners). Through the open source release they emphasize their commitment to open science. ICON is the product of close collaboration between research and national weather services: the close cooperation results in very efficient weather forecasts and climate projections. Open and transparent scientific tools strengthen the science at a time when society is in critical need of better early warnings from natural hazards, and a clearer picture of the changing climate, which benefit not only the research community, but above all society. Making the code publicly available is an important step towards strengthening trust in science and the institutions.

Oliver Fuhrer, Head of the Numerical Forecasting Department at MeteoSwiss, emphasises this: "The open source availability of the ICON model marks a decisive moment in meteorological research. The ICON model is currently in the test phase with the goal of deploying it for daily weather forecasts this year."

ICON was initially developed jointly by DWD and MPI-M as an atmospheric and weather forecasting model and is now used in Germany and Switzerland for operational weather forecasting. With regard to climate research, the MPI-M has developed further suitable models of other components of the Earth system that allow ICON to be used as a fully coupled climate and Earth system model. To ensure that the simulations can also be used and efficiently calculated on the world's fastest supercomputers, the C2SM partners ETH and MeteoSwiss, together with the MPI-M, DKRZ and DWD, developed an ICON version that can run efficiently on GPUs (Graphics Processing Units).

The specially developed community interface ComIn, for example, enables scientists to extend the ICON model with their own plug-ins without having to change the complex model code. This not only promotes flexibility in research, but also fosters innovation within the scientific community. Nicolas Gruber, ETH Zurich and C2SM representative on the ICON Board of Directors, emphasises the importance of open source as a driver for research: "Open access to the code allows researchers to develop models much faster and increase scientific transparency, which is particularly important for climate projections".

All submodels are included in the open source release, so that ICON can be used in the most diverse resolutions and configurations to enable a whole range of applications — from global and regional weather forecasts and climate projections to very high-resolution digital twins of the Earth system.

Open Access to Science and Innovation

Making the ICON model code available under an open source license is a major step towards open, transparent, quality-assured and collaborative science. Researchers worldwide will have the opportunity to build on one of the leading models for weather forecasts and climate simulations and work together on future-oriented projects. Commercial use is also possible under the license. The publication takes place in the context of a changing research landscape that promotes increased collaboration and the exchange of knowledge.

The open source release facilitates the integration of ICON into international research collaborations and strengthens Europe’s position in the field of climate and weather research. It also enables a more efficient collaboration with supercomputer vendors, who can test and improve the performance of their hardware using weather and climate models.


MeteoSwiss Communications
Tel +41 58 460 97 00

C2SM Communications
Tel +41 44 633 84 58