Sometimes a season (summer) is not behaving the way you want it to behave. For example, it's wet and cool, but at the same time really humid, so it's not like you're spared from sweating all day. If so, it's easy to submerge yourself in a totally fake but completely awesome version of said season (summer) by reading seriously seasony (summery) books.
Dandelion Wine by Ray Bradbury. Sort of science fiction, sort of fantasy, very nostalgic, totally summer.
Criss-Cross by Lynne Rae Perkins. A lazy, meandering summer story about self discovery in a small town.
Mother Cary's Chickens by Kate Douglas Wiggin. Charming, old fashioned, romantic and so summery!
Hope Was Here by Joan Bauer. Takes place during many seasons, but is summery none the less. Lots of good food, very comforting.
I'm really bad at writing blurbs about books, but trust me, they are all very good!