...
ecCodes seems to handle this information correctly when using grib_to_netcdf (i.e., the first step in the resulting netcdf file is July 2022) but when opening the grib file with cdo or python's xarray (cfgrib backend) the data gets a valid date coordinate that I assume it derives from 'validityDate' (or the actual addition of 'step' to 'dataDate'), i.e., no valid data in July.
Am I correct in assuming that the first forecast step in the downloaded file above is the monthly mean temperature for July? If so, what is the actual defintion of the grib keywords 'validityDate' (and related to this the meaning of 'step') for the monthly statistics? Is it (always) the end date of the monthly aggregation window (which would be the only way I could make sense of it here)? Is this specified somewhere?
...