You can have a sky utterly devoid of light pollution and iit still be utterly useless for astronomy by dint of driving rain or scudding cloud, even withut the precipitation. With around 2/3 of nights unusable, that is the main reason that I shipped my telescope off to my sister's country guest house. On those rare occasions that it does get used, it`s much better there than in my home town. But that`s still only a few nights a year that it gets used.
Going back to the original question - what is the most effective use for getting kids interested in astronomy (or whatever the Q was - I can't remember now) - then choosing your time and place is going to be important. Making a big build up and then being washed out by the rain (or snow, or in high summer, fog) is going to be more effective dampener than taking an opportunity of good conditions and using it there and then.