I'll forever remember the greatest year in all of music...1966, and especially that summer.
Everything was full speed ahead, with the British Invasion taking hold with the Beatles, Stones and the like...and North America fighting back with the Beach Boys' Good Vibrations and the Lovin' Spoonful's Summer in the City.
One more Oasis song -- Round Are Way. There's a shot of Ewan McGregor singing the wonderful chorus, all loud and happy and carefree in the movie A Life Less Ordinary. And then at the end of the movie, the original song plays over the credits. This song is SUCH a summer song.
Well, i agree with Mexicanuck (In the summer Time - Mungo Jerry, Summertime Blues - Blue Cheer) and Chumley (Sunny Days - Lighthouse). I also remember Coconout- Harry Nillson and for the summer of 73 (for me anyway) July Morning - Uriah Heep. Interesting that this song is now part of an annual festival in Bulgaria (of all places).