The Balearics have the reputation of being fantastic islands for partying... But it would be a shame to limit to this these wonderful islands, with numerous creeks and warm waters, easily accessible by sea and by air...
If you like long passages and night watches, and you are envisaging a cruise of at least two to three weeks, you can think about leaving from the ports in the Languedoc-Rousillon region of France, the Costa Brava (Barcelona), or again, the ports on the Var coast, for example. But it is a long way to the Balearics, and you will have to allow four or five days for the return trip, in good conditions.
Another solution: charter locally, where there is an abundant supply of boats, and simply enjoy your cruise locally.
The climate is Mediterranean, hot in summer and pleasant mid-season.
In summer, the Balearic Islands benefit mainly from sea breeze conditions: a diurnal sea breeze starting to blow gently at the end of the morning, to end up, at the end of the afternoon, sometimes blowing quite violently (20 to 25 knots). However the north-north-westerly wind (Mistral-Tramontane) can blow for several days; it will be felt above all on Minorca and the north-north-west side of Majorca.
Ibiza and Formentera, further south and west, are not affected by this wind; they receive a system of winds almost identical to that in the Valencia region (light to moderate easterlies). A night breeze can start to blow in the middle of the night, to die at sunrise, thus allowing some nice passages between the islands.
The Balearics are Spanish, and therefore have the same rules as in the European Union.
The money is the euro, and credit cards are accepted everywhere.