There are days in Minnesota, usually immediately following a series of long, hot, muggy 24-hour affairs, when you can tell that summer has lost its stranglehold. Air from Canada settles in and the difference is immediately apparent. Cool, dry, fall air.
At this point I've managed to forget the nastiness of the winter so it comes as a bit of a shock to realize it's almost back on the doorstep. It makes the season seem a little more precious.