I feel a little bit ashamed that you have no luck with the weather. It is amazing how many nights we have had very good observing conditions this year. But there is to mention that especially near the whole May + the first part of June I had very many nights w-i-t-h-o-u-t NLC. The first observation I made was from 16th to 17th of June. But you know, too, that this season seemed to start late - with a markable ending of course!
My observations of Aurora Borealis, NLC + PSC, additional hyperlinks to weather satellite images: 3sky.de