We had a really mild summer this year. The only time I ever turn on my air conditioning is if it's a really hot night and I can't sleep; and this year, I only used it twice. There's just something about sleeping with my windows open and a breeze blowing through.
Even though it's getting a little cooler in the evenings, I don't want to give up the night air just yet, so I've already put an extra blanket on my bed, with another close by in case it gets particularly chilly. It makes it even harder to get up in the morning when my bed is so soft and warm, but it's worth it.