[Shaun]

Hmm that I recall...

2006 - Hips Don't Lie by Shakira... that kept doing battle with SexyBack and My Love from what I recall of that summer...
2007 - Umbrella obviously but for me 'With Every Heartbeat' by Kleerup/Robyn and 'Song 4 Mutya' were my favourites then.
2008 - That Guru Josh Project song (Infinity 08) stands out immediately to me as being the song that was on every bloody week that summer at clubs. RIP </3 but also September's Cry for You? And Estelle's American Boy was indomitable.
2009 - When Love Takes Over and I Gotta Feeling are the obvious standouts but I'd also say Kasabian's "Fire", Florence's "Dog Days Are Over" and Example's "Watch the Sun Come Up" for me. Oh and Empire of the Sun!!!! We are the People
2010 - The Drums' "Let's Go Surfing", Gorillaz' "On Melancholy Hill", Scissor Sisters' "Skin Tight" and M.I.A.'s "XXXO" were played a lot by me... from the charts I'd say Teenage Dream and Swedish House Mafia? ... oh and Sleigh Bells' "Rill Rill" is a great summer song.
2011 - Beyonce's Party hands down. But for the sake of padding this list out... Bombay Bicycle Club's "Shuffle", Cut Copy's "Where I'm Going", Foster the People's "Pumped Up Kicks"... the charts? Definitely Stereo Love and On the Floor. Personally loved the Go! Team's "Buy Nothing Day", v summery.
2012 - I pretty much listened to Grimes' "Oblivion" all summer but Calvin Harris was releasing 10/10 singles - Bounce We'll Be Coming Back Sweet Nothing - Feel So Close in particular was a very "reminds me of uni" song. Oh and even though they wouldn't go #1 til the next year, Icona Pop's I Love It.
2013 - Ciara's "Body Party", obviously the charts were killed by Get Lucky + Blurred Lines... Disclosure's album was played a lot so I'd say When a Fire Starts to Burn from that
2014 - Duke Dumont's I Got U is the easy winner. Played "Dibby Dibby Sound" a hell of a lot too. Kiesza's Hideaway.
2015 - idk what was on the COL playlists tbh... Alesso's Sweet Escape, Carly's I Really Like You, Indiana's Solo Dancing, I played Jamie xx's album a lot... Bieber didn't really emerge til Autumn did he? Lilly Wood & The Prick seemed to be everywhere. And Lean On obviously.
2016 - I just kept playing Rihanna's Kiss It Better tbh I don't know what the defining song of last summer was?

I know I've done waaaaay more than I needed to so I'll just go back and bold the ones I'd say defined it for me