Hi!
I grew up in Barcelona and lived just under the French border for 10 years before I moved here. A few references below:
1) BARCELONA: The winds during summer tend to be light (or very light), and you're going to need volume and a big sail to plane. Of course there can be exceptions to the rule, but you will have to follow the forecast. If you encounter good conditions when you're in BCN and feel like going to the water, you can hire material from any of the 2 links below:
http://magicwave.es/rent/ www.flowwatersports.com/#!rentals/c1egl 2) WHEN DRIVING UP TO FRANCE: GOLF DE ROSES I would recommend to stop by in Costa Brava, preferably up north in around Sant Pere Pescador, staying either in L'Escala or in any of the many caravan parks in the area. This is where I lived and it's a great place to enjoy windsurf, relax, enjoy great mediterranean food and do many outdoor activities with the family. I you're interested PM and I can give you more details.
For renting windsurf gear, go to the ex-Mistral Club, now ION club, right in the middle of the Golf the Roses.
www.ionclubgolfderoses.com/windsurfing.html If you can go a bit earlier, on June 10-12th, there is the popular "Surf Alegre", which is a fun weekend where 400 to 500 windsurfers get together in the camping "Ballena Alegre", also in Sant Pere Pescador.
The wind during this period picks up around midday, around 2ish, and a 115 l. board with a 6m2 sails is the most frequent gear combination. However, look at the forecast or speak with the locals to see if you can catch a day with a wind called
TRAMUNTANA, which is a strong northerly wind that can blow at 30, 40 or even 50 knots (yes, it's very strong)... this is why the locals have 3m2 sail in their stash over there! Unfortunately, Tramuntana is more common from September, through the winter and up until May... however sometimes you're lucky and get it a few days in summer too.
3) SOUTH OF FRANCE: LEUCATE As ned mentioned, Leucate and La Franqui (just a few km's above leucate) are the places to go. The conditions are very similar to those in Golf the Roses.
Places to hire windsurf gear:
www.ile-des-pecheurs.com/pages/funclub.php?lang=gb www.surfone-leucate.com/ Again, feel free to PM me if you have specific questions, particularly for BCN and the Costa Brava areas.