When searching for our cruise details I found your comment on cruise chat. We have booked the same Mediterranean cruise, but we will start already on 28th September 2008 in Barcelona (4 days left...). It is our 6th cruise (former with MSC, AIDA, Costa) but the first with NCL. My wife will celebrate the 40th birthday too during this cruise. And our cabin is also on deck 9. What a coincidence ! If you like, I will answer all your questions, when I am back. But I have no idea, how to contact you. Nevertheless - if you are interested in - I come from Germany and my home is 1 mile far away from the next cruise harbour. There I saw the NCL Jewel - the same ship as the Gem - several times from my window. And now we will start our own cruise...
And I visited the Mediterranean Sea several times in October and November. You can expect temperatures between 20 and 28°C. Both sunny and rainy days are possible. So it is difficult to decide what clothes you need.