aceptamos:

Barcelona has a Mediterranean climate, so the weather in Barcelona is pleasant most of the year. However, you will have the best weather from May to late July. September is also a good month. August can be hot during the day (sometimes reaches 34 ° C, 95F).
The weather in October and November is still pleasant but starting to be a little cooler (21 ° C down to 15 ° C, 69 to 59F). You will not see a bright sun every day, so be prepared for days that are expected a little rain. Remember that these are only indications and the weather can vary somewhat from year to year. Especially in the last few years there have been fluctuations.
From November to February temperatures in Barcelona are colder and vary around 12 ° C or 53F. During the winter, here does not usually rain, so even though it is colder, there will be many sunny days.