Some reports I have read suggest August is not a good time of the year to visit Barcelona because of high temperatures & humidity and also because a number of small shops & restaurants are closed down for the month. I would be interested to hear from anyone who has visited in August previously.

Barcelona in August is extemely crowded with tourists, including day-trippers from nearby resorts. All sites and services of interest to tourists will be open. This goes for shops and restaurants - the exceptions being small neighbourhood places and others catering mainly to locals. Some gourmet places may close part of August. As for temperatures, it can get hot and humid, but being on the sea it's more bearable (compared to, say, Madrid, Granada or Seville), and air-con is pretty universal except in smallest pensions.

I'm interested in this also, not for this year but possibly next summer. My only options for travel times are one week (maybe 10 days) in March or as long as I can afford (probably at least 2-3 weeks) in July or August. I really want to see Spain but all the horror stories about heat have me considering trying to squeeze it in in March, but I know 10 days is not enough to see much. I would want to go other places besides Barcelona, but could probably live without Madrid. I think Seville and Granda would be high on my list. Which trip (10 days March or 3 weeks July/Aug) would you pick?

Have been to Barcelona in Jun - too hot!
Take the 3 weeks and go somewhere else or be prepared to suffer the heat coming up from the pavements.
Meira

I've been to Barcelona in August twice. It is hot and it is humid...it is NOT a time to "wonder" if you need air conditioning in a hotel.

It wasn't any more "crowded" than a lot of other places I've been in August..always helps to start out early in the day to beat some of the crowds but if that is the only time you can travel I would advise you to go for it...great city and what seems "crowded" to some may seem like a piece of cake to a more experienced traveler.