(I’m not asking for you to list your ideal “beach reading,” you understand, but the book that you can read at any time of year but that evokes “summer.”)
The book that evokes that summer feeling for me is Child of My Heart by Alice McDermott. It is about a teen-aged girl who is left in charge of her cousin for the summer. The sense of summer is clear throughout the book and I loved it. It brought back memories of summers spent visiting my dad who worked all day and left my sister and I to explore in the evenings. It is one of my favorite books.