When it comes to picking the best time to travel to Barcelona, you really do have an open playing field. The city has two main seasons (summer and winter) with only a few transitional months.
Summers are hot and humid. Temperatures reach 30°C and above. If you wish to explore the beaches, now’s the time to go. In contrast, winters get as low as 14°C. However, Barcelona isn’t an especially wet or windy city, so getting out and about is still very much on the agenda.
Barcelona also gets a consistent amount of daylight throughout the year. No need to worry about the sun setting on you before you’re done exploring.