The Online Laboratory for Climate Science and Meteorology (
https://lab.climet.eu) provides a JupyterLab-like environment that has common climate and meteorology packages and libraries (e.g. eccodes) preinstalled. Unlike a typical JupyterLab instance which requires a server to host all running Python sessions, the online lab is serverless (just a static website) and runs entirely inside the user’s webbrowser using WebAssembly. It builds on the existing Pyodide and the JupyterLite projects, which provide Python/JupyterLab in the webbrowser using WebAssembly. Our contribution are (1) that several weather and climate packages can now run in this environment and (2) several transparent-to-the-user patches to these and other packages to ensure that the same code runs in the online lab just as it would in a local installation. Overall, the online lab provides researchers an installation-free quick-to-launch Jupyter environment in their web browser that can be used for running small experiments, sharing notebooks, and hosting interactive documentation. For example, the Online Compression Laboratory (
https://compression.lab.climet.eu) hosts the compression laboratory notebooks (R31) using the online laboratory so that anyone can get started trying out compression on weather and climate data without any setup in ~1min. The initial prototype (-2023/11) was primarily focused on the technical infrastructure of the online lab, i.e. getting critical Python libraries for weather and climate science to work in the new environment (see above) and implementing data streaming to support working with large datasets in the memory-constrained webbrowser environment. The initial releases v0.1.0 and v0.2.0 provided support for additional packages, improved user convenience, and added the needed functionality to host the online compression laboratory.