Open Data policies have become both popular and mandatory across Europe. While several countries and institutions have adopted already a wide open data policy, the EU Open Data Directive  is changing the landscape even more in the coming years.
In meteorology and climate science, a variety of European and international Open Data services grant access to a growing amount of open datasets. Open Data related to weather and climate consist of several different data sources and space/time coverages. For instance, near-real-time weather station measurements, radar-based and satellite-based observations and nowcasting products, model analyses and forecasts, climate data, as well as datasets for experts in emergency management, agriculture, road maintenance, and many more specialised fields are widely provided as open data.
To tame the variety and sheer amount of data, humans rely on computational support and standardised automated ways to treat data and metadata. Popular interfaces are data portals for human interaction and APIs for machine/automated interaction. RESTful APIs are a popular choice as well as GeoWebServices, e.g. in OGC compatible WMS and WFS formats.
Additionally, it is more and more common to exploit clouds to distribute and process Open Data. Initiatives like WEkEO , European Weather Cloud , and Open Data on AWS  are specially built to bring users to data and make processing large data sets easier.
Since all of this Open Data can be freely used, modified, and shared by anyone for any purpose, numerous applications based on these datasets have been developed in the public and private sectors, by met services, companies, research institutes, and open source developers.
The aim of the session is to bring together the enablers, providers, and current/future users of Open Data in meteorology and climate, to share their experiences and requirements.
We invite contributions on both technical and user-focused topics related to
- New Open Data sets including hosting Open Data on-premise and in the cloud
- Metadata management including FAIR principles 
- Effects of and preparing for the new EU Open Data Directive
- Tools and interfaces (APIs) for accessing and utilizing Open Data
- How open data cloud-formats, such as Zarr and COG, play together with the new OGC APIs 
- The development of data portals, including catalogue services, download services, visualisation services, transformation services
- Existing Open Data applications using weather or climate data
- New ideas where and how Open Data can serve society
- Opportunities and challenges regarding Open Data, including data sources, data formats, legal issues ...
- Community building: How open data in weather and climate can be used and reused in various organisations, and where people can easily build on each other's work, and easily go somewhere to ask questions.
- Whatever you feel is necessary to tell about Open Data