Benchmarked strictly across TripTiming's 5 empirical pillars: Crowds, Weather, Vibes, Prices, and Safety.
Copenhagen emerges as the optimal September destination with an overall TripTiming Index of 70/100 vs 62/100 for Amsterdam (+8 point advantage). Copenhagen experiences substantially lower visitor footfall and shorter landmark queues (moderate footfall vs heavy visitor congestion in Amsterdam). Sightseeing is further aided by comfortable outdoor weather (17°C feels-like). Travelers also benefit from lower accommodation costs (~$281/night vs ~$312/night in Amsterdam, saving ~$217 over a week). While Amsterdam retains an edge in City Vitality (61/100 vs 45/100), Copenhagen's commanding performance in Space & Crowds secures the overall September recommendation.