Well, I'm slowly bringing out my fall stuff but not putting the sandals and sundresses away yet. Today it's in the 60s in boston but it's supposed to go back up to 80s by the end of the week. And I have a trip to Greece planned for early October, I'm told it will still be quite warm there at that time so I am planning to bring some of my more summery things.
ETA: the only things I really switch out in the closet are my shoes and even then the off-season things are still pretty easy to get to. Everything else pretty much stays in the same place all year, so I am lucky that I get to pick from almost all of my clothes every morning depending on the weather. If you're doing the full seasonal switch, that's tougher.