I don’t know when it was decided that we needed an official “song of the summer,” but some time ago that happened. It’s something we need now. Last summer belonged to “I Love It” by Icona Pop feat. Charli XCX, until “Blurred Lines” had stolen it by Labor Day. Miley Cyrus’ “Party in the USA” was a song of the summer a few years back.
To be song of the summer, the criteria is simple: It needs to be beyond catchy, everyone needs to know the words, and it has to be played so often that it gets seared into your brain.