Weather will likely play an important role when you plan your trip to Barcelona, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually June and May, with an average temperature of 28°C, while the coldest months are February and January, with an average of 26°C. The rainiest months in Barcelona are December, January, November and July, with each month seeing an average of 400 mm of rainfall.