Would it be possible to add the option for multiple versions of skies (i.e. clearsky1, clearsky2, clearsky3 etc) to be added to .amb and then the engine randomly (or they could be in order of cloudiness/weather intensity) selects one for the session ?
Might be an easy way to add some visual variation to sessions at the same track and give the illusion of weather.
In addition to "sky", it is also possible to set "sky2" and "sky3".