Benchmarked strictly across TripTiming's 5 empirical pillars: Crowds, Weather, Vibes, Prices, and Safety.
Barcelona emerges as the optimal May destination with an overall TripTiming Index of 62/100 vs 59/100 for Rome (+3 point advantage). Barcelona experiences substantially lower visitor footfall and shorter landmark queues (heavy visitor congestion vs peak seasonal crowding in Rome). This is reinforced by lower lodging rates (~$319/night vs ~$378/night, saving ~$413 over 7 nights). While Rome retains an edge in City Vitality (81/100 vs 65/100), Barcelona's commanding performance in Space & Crowds secures the overall May recommendation.