What to wear
Summers in El Born at the Heart of Barcelona, are hot and by many standard humid. So dress lightly and with style. As a major cosmopolitan city the people of Barcelona have great casual fashion sense, and you can too when you visit after a chance to shop in some of the many boutiques in the area.
T-Shirts and jeans will take you far in the city, particularly if they have a little flair. Sports shoes are common as are sandals but with custom boot and shoe makers abounding in the city such footwear is also common.
Despite how close to the beach the district is though beach wear is only suitable for the beach, and not in the city.
All of northern Spain can be cold in the winter, particularly once the sun has set in the afternoon. Hence some woolen clothes and a good jacket will take you far.
Catalonian ladies are known for their sense of style, so ladies who wish to fit in with the local scene in clubs etc should be prepared to dress up just a little more than perhaps would be normal at home.
When visiting places of worship it is considered respectful to wear a little more conservative attire. E.g. shoulders and knees covered.