My wife and I are debating between London and Barcelona for August, the only month we are free to travel. The Weather Channel gives 82 degrees F. as the average in B. for August. But I ask travelers: how hot does it get??? And also, given the unemployment, is street crime any/no worse than in the past, when it was mainly pickpockets? (I know: wear a money belt! I always do. But I'm wondering about muggings.) So how muggy does it get in August, and is the threat of mugging low or otherwise?
I can't really speak to the crime because we haven't exprienced anything bad in Barcelona. I can certainly speak to the heat though! It is HOT with a capital H. Even if you're close to the water be prepared for heat. AC is not common unless you plan to stay in a pricier hotel. Most Spaniards flee the city in August. Those who stay along with the tourists generally don't go out during the day limiting their outdoor time to the mornings and evenings. Dinner is very typically around 10 or 11 at night when it is a bit cooler and sleep or close themselves inside during the heat of the day. You can do it just be prepared!
That said...I've also been in London during August and it can be hot there as well. Sometimes I've been there and it's been lovely and other summers it's been drought conditions and very hot. Less likely to be hot than Barcelona though! That's pretty much a guarantee...
Violent crime, like mugging, is relatively rare, and has not increased due to Spain's unemployment situation. I walked around alone in both Madrid and Barcelona, and never felt unsafe. I take the normal precautions that I would in any city, and didn't stress about it too much.
I've been to Barcelona twice in the past few years near that time. It will be HOT for sure, but plan appropriately and drink lots of water and you'll be fine. As for crime, it didn't seem to be anything other than pickpockets. They are pretty bold and seemed to be more of it than the other cities we were in, but no violence. My experience in Barcelona is you are more likely to run into a political demonstration there too - I would just try to avoid them.
We spent three days in Barcelona this April, felt not one twinge of worry about our safety anywhere in B. or Spain nor did even we notice any situation where anyone else was at risk. A pleasant surprise as we had much the same concern you voice. Money belts always, I never carry a purse, husband carries a small sling backpack. Consider an apartment rental with AC? We used airbnb for a one bedroom which did have AC. Marian