To be serious for a moment.
July is the height of summer. It's the best time for going out and doing things that are not reading. Non-fiction tends to be larger books. July is one of the wort months for reading such tombs. August is no good as well as it's the time to spend with the Kinds before school starts. September is no good as that's the ending of the summer. October or November would better be served with such possibly large tombs.
So let's give October or November to non-fiction and let Science-Fiction have July.