[K-man]

It must be because Budapest does not have access to a beach. Slovenia borders on the sea. In Bulgaria, it's the same thing - if you go June-July-August, skip the large cities and head straight to be beach, as everyone is there. Of course, not all can afford to skip town and stay at the beach all summer, but they at least drive there for the weekend, so during weekdays they save their energy and money for the weekend beach party, and there is not much nightlife in the cities.