Just drank a root beer float.
I'm not fond of root beer most days, but something about summer and adding vanilla ice cream and there you have it -- a glass full of yum. I associate root beer with summer anyway. Growing up in Chicago, I lived walking distance from the lake, which meant walking distance from the beaches as well. In the summer they'd open up the refreshment stands and you could buy a paper cup of root beer, which always tasted better on the beach somehow. That strong taste and smell mixed with the aromas of Lake Michigan -- water and sand and suntan lotion and sometimes dead alewives, which were these fish that on occasion died in wanton abundance and washed up on the sand. Not a good smell, that. But summer anyway.
And cherries - they define summer for me, too.
Yes, I know you can buy them out of season from Chile, but I refuse. I want Michigan cherries or Washington cherries or wherever they're growing here, nearer to me. (This is a longer rant, but I will spare you)
What food/drink says summer to you?