Not all tourism destinations are created equal. Spain is one of the world’s biggest magnets for international travellers: only the US and France receive more visitors. But not all its cities receive the same sort of visitors. This chart suggests that Spain has tapped into at least two distinct markets.

Bed occupancy rates. Source: CityMetric Intelligence.

There’s a clear difference in the timing of peak tourism season in the three different cities. Barcelona and Valencia both lie on the coast, so it’s probably no coincidence that both report their highest occupancy rates in the summer months: for all their many cultural draws, both get a lot of travellers seeking sea, sun and sangria.

That’s particularly true of Valencia, where visitor numbers peak sharply every August, but rapidly tail off again. In Barcelona, by contrast, the season lasts from April to October.

Madrid, though, is 360km from the nearest beach (which is, in fact, in Valencia). Hotels in the capital are relatively quiet in the height of summer: instead, they record their highest occupancy rates in spring and autumn.

At first glance one might put this down to the city’s outstanding restaurants, museums and galleries – but the other cities can boast plenty of those, too. The excitingly named International Congress and Convention Association suggests another explanation: in a 2013 report, it ranked Madrid as the fourth most popular city in the world for international business conferences. In all, according to the Madrid Convention Bureau, the city hosted 200 conferences and 117 other events in 2013.

There’s one other thing to note about this chart: even in the peak months, Madrid’s hotels are never more than 60 per cent occupied. In the peak months in Barcelona, that number gets as high as 83 per cent. In other words, whatever other attractions Madrid has, it’s cursed with far too many hotels.