Great thread! I'm in a pub in Croatia watching football on vacation and hope this link sounds alright.
Quite sure i will be slammed for at least 487 reasons, and 488 of these will be right, but without going too back in time i like that:
Songs about summer, or songs that were released in the summer? "Boys of Summer" by Don Henley came out in the dead of winter in 1985, but the lyrics reflected that bleakness.
There are songs that mention summer and those that I associate with summer due to when they were hits. I did a post on Pop Culture Safari blog last year focused on summertime hits. Might be of interest to those here: Pop Culture Safari!: Pop Focus: Hit summer songs of the 60s and 70s »
A few years ago I read an interesting article on how the prognosticators try to determine the song of the summer. That year, most bets were on "Call Me Maybe" by Carly Rae Jepsen, and of course, they turned out to be correct.
From one of the most pivotal and musically rich summers ever -- 1967 -- come on baby "Light My Fire".