The cl-files are designed for holding climate or normal weather data. The cl-files contain time series data just as aio-files do and a cl-file with the same version number as an aio-file also contains the same columns, but contains data for exactly one year, and the values for a specific hour a particular day of the year should represent the typical weather for that moment of the year. These files are created from weather observation data in aio-files in the utility software Aiolos File Studio.