The AIFS is ECMWF's data-driven Artificial Intelligence Forecasting System.

The IFS is ECMWF's traditional physics-based Integrated Forecasting System.

Users can refer to our scorecards, which evaluate and compare the performance of the current operational versions of the AIFS and IFS.

• AIFS Single vs IFS
• AIFS ENS vs IFS

Details of how to interpret skill scores is provided in our Forecast User Guide: Section 6.2 Relative Skill of IFS Models 

For further context, users are also encouraged to review our documented known forecast issues for each of the models:

• Known AIFS Single forecasting issues
• Known AIFS ENS forecasting issues
• Known IFS forecasting issues