Just like rotating toys helps to keep them fresh, rotating books in and out of your child's library also brings some surprise to reading. We rotate a small batch of six or seven books seasonally in our house.
While it's certainly not true that you can't read a book about blossoming trees in winter or a book about snow crystals in the summer, organizing at least a few books by season is a great way to introduce and teach the seasons. If you don't have a whole bunch of books about summer or autumn, checking them out each year at your local library is an easy way to rotate them.
Over at Rhythm of the Home, Bernadette actually went a step further and had her kids paint bookmarks and labels for each season and store each one in its own special box. We just store ours in a bin for not yet given toys or books in our closet, and place them on our forward facing IKEA picture rail when it's time.
In our experience, anything that makes a seasonal entrance (Easter baskets and eggs, a Nativity set), is considered quite special. It seems like a great thing to bestow upon books as well.
Do you rotate any books by season?