Some of the parameters can assume special values which are not to be taken literally, but are codes for special cases or conditions. The codes currently in the system are listed below.
The parameters acc_precip, max_precip_past24h, acc_precip_past12h, acc_precip_past24h and max_precip_30m return the amount of precipitation within the given period in mm with the exception of the codes listed below.
traces of precipitation, less than 0.1 kg/m2
Wind direction codes
The parameters mean_wind_dir & mean_wind_dir_min0 return the direction from which the wind blows in degrees, where north is given as 360.
Cloud cover codes
The parameter mean_cloud_cover is reported in oktas (eights) and is the fraction of the sky covered by cloud of any type or height above the ground.
0 oktas - no clouds
1 okta or less, but not zero
7 oktas or more, but not 8 oktas
8 oktas - full cloud cover with no breaks
Sky obscured by fog and/or other meteorological phenomena