ya its an awsome song but to me a summer song has to be summerish! And this has nothing summer ish a bout it!
Dangerous - Kardinal Offishall Ft. Akon
or
Just Dance - Lady Gaga Ft. Coldy O'Donis
are better candidates
I think by saying "Song of Summer", that OP is stating that IKAG is the most popular song of the summer, which is 100% true. And while the other songs you mentioned might have a more "summer" vibe, they aren't nearly as successful as IKAG is.
I Kissed A Girl & I Liked It
The Taste Of Her Cherry Chapstick
I Kissed A Girl Just To Try It
I Hope My Boyfriend Don't Mind It
It Felt So Wrong, It Felt So Right
But It Don't Mean I'm In Love Tonight
I Kissed A Girl & I Liked It, I Liked It