On the highest hierarchy level of the dictionary, i.e. as neighbour to 'city', 'site', 'date', 'daily', 'hourly', the dictionary has to have another entry 'prediction_time', that denotes the time when the html file was downloaded as an int in the format YYYYMMDDHHMM. This should be easy to implement, since this timestamp is included in the file names.
This information then has to be stored in an additional column in the hourly database.
From #23: