Spring (April-June) offers ideal conditions warm temperatures (18-25°C), manageable crowds, and outdoor festival season including Sant Jordi (April 23). Parks and gardens bloom beautifully.
Fall (September-October) provides similarly excellent weather after summer crowds depart. La Mercè festival (late September) showcases Catalan culture with free events citywide.
Summer (July-August) brings heat (25-30°C+), maximum tourists, and some local businesses closing for holidays. Beach season peaks but expect crowds. Many free outdoor concerts and cinema screenings.
Winter (November-March) sees fewer tourists, lowest prices, and mild temperatures (10-15°C). Christmas markets add charm though some attractions have reduced hours. Perfect for museum-focused visits.
Avoid if possible: Easter week, August, and major trade fairs (check convention calendar) when accommodation prices spike.