Consider visiting Barcelona in late April through early June or mid-September through October for the ideal combination of pleasant weather, manageable crowds, and cultural vibrancy. Spring brings average temperatures of 15-22°C (59-72°F), perfect for walking tours through Gothic Quarter's narrow streets and hiking Montserrat without the exhausting summer heat. The city blooms with jacaranda trees painting the Eixample district purple, and outdoor terraces reopen after winter. May hosts Primavera Sound music festival if you're interested, though book accommodations well ahead. Autumn offers similarly comfortable temperatures with the added bonus of harvest season—wine regions surrounding Barcelona celebrate verema (grape harvest) with festivals and tastings, and restaurants feature seasonal mushrooms and game on their menus.
Summer (July-August) means peak tourist season with temperatures often exceeding 30°C (86°F), packed attractions requiring advance reservations weeks ahead, and higher accommodation prices. Many locals flee the city for vacation, so some neighborhood restaurants close, though beach clubs and outdoor venues thrive. Winter (November-March) sees fewer tourists and lower prices, but some outdoor activities become less appealing in 10-15°C (50-59°F) weather with occasional rain. However, winter offers excellent museum-hopping conditions, shorter lines at major sites, and the magic of Christmas markets in December.
For your interests in hiking, outdoor photography, and exploring markets, spring and autumn deliver optimal conditions. The Mediterranean light during these seasons creates that coveted golden glow photographers dream of, particularly when illuminating Gaudí's mosaic work. Markets overflow with seasonal produce, cooking classes feature fresh ingredients at their peak, and hiking trails on Montserrat offer clear views without summer haze or winter cloud cover obscuring the monastery.