Most paragliding in Barcelona is done somewhat north of the city. A place called Berga has a particularly good reputation.
Barcelona is the second largest city in Spain, and is the capital of the region called Catalonia. The city sits on a small plateau facing the Mediterranean sea, between the mouths of the rivers Llobregat to the south and the Besòs to the north.
About 160 km (100 miles) to the north rise the famous Pyrenees range of mountains, although you start getting into the foothills only 80 km or so away from the city. The Pyrenees form a natural border between France and Spain, in southwest Europe.
The weather is pretty mild all year round. This plus the presence of mountains, hills and sea has made all kinds of outdoor sports popular in this region!
Barcelona has a Mediterranean climate. Duhh. You can't get much more Mediterranean can you, with the sea of the same name just a short drive away! Winters here are mild and dry while summers tend to be warm and humid. Summers can often be uncomfortably windy for paragliding in Barcelona! Or great for para-waiting, whichever way you look at it.
January and February are the coldest months, with average temperatures around 10°C (50°F). Not cold at all by most counties' standards. July and August are the hottest months with average temperatures of 25°C (77°F). Nice for paragliding! In August 2003 the highest ever maximum temperature was recorded, at 38.6ºC (101.5°F).
Apparently the best place to do paragliding in Barcelona is in Berga, around 100 km (60 miles) north of Barcelona in the foothills of the Pyrenees. After spending some time in a paragliding forum I discovered some pilots who really thought highly of the location.
According to one of the local flying schools there, the main meeting point for those intending to fly is 4 km (2.5 miles) west from Berga. A spot called Casa Sobrestrada. There you will find a range of facilities including a 4 hectare flat grassy landing zone, the local training slope, swimming-pool, restaurant, coffee shop, parking, classrooms, even a paragliding repair shop!
Some visiting pilots get a bus there from Barcelona, or hire a car which is quite cheap. The local school, Espais, are the people to contact to arrange flying, transport to launch sites and so on.
You might want to avoid flying at Berga during summer since it can be rather windy. The locals say the best months to go paragliding in Barcelona are spring and autumn.
I came across a great summary of flying at this location, so I'll just quote it here...
The main sites flown seem to be the Marias (effectively the first foothills of the Pyrenees) with Maria 1 immediately above the school being most often flown mid-morning when top-to-bottom flights are more likely, and Maria 2 flown towards lunchtime and for afternoon/evening flights. A mid-morning flight from the 2000m launch above the Rasos de Peguera through the col in the Queralt ridge and down to Avia is quite cool, and normally it's possible to jump back from the Marias onto the Queralt ridge once the Marias are working.
Of course Berga isn't the only good place to go paragliding in Barcelona. The Àger valley has a number of paragliding operators, around a place called Lleida. One of these is the Albatross School. These guys do introductory tandem flights too, if that's more your style. Very quaintly called 'baptism flights', they used to cost around 60€. Don't quote me on that price!
If you're planning a visit to Barcelona soon, it might be handy to check out Barcelona city breaks - short term apartment rentals.