  WeatherBench 2 is an update to the global, medium-range (1-14 day) weather
forecasting benchmark proposed by Rasp et al. (2020), designed with the aim to
accelerate progress in data-driven weather modeling. WeatherBench 2 consists of
an open-source evaluation framework, publicly available training, ground truth
and baseline data as well as a continuously updated website with the latest
metrics and state-of-the-art models:
https://sites.research.google/weatherbench. This paper describes the design
principles of the evaluation framework and presents results for current
state-of-the-art physical and data-driven weather models. The metrics are based
on established practices for evaluating weather forecasts at leading
operational weather centers. We define a set of headline scores to provide an
overview of model performance. In addition, we also discuss caveats in the
current evaluation setup and challenges for the future of data-driven weather
forecasting.
