I just walked outside this evening. The "peepers" (tree frogs, I think) were incredibly loud. They generally start making noise in late January or early February. While it's still winter, these little frogs are a signal that spring is coming (as are the sandhill cranes we'll hear and see later this month).
We almost always have a day in late August that feels like autumn - it's a bit cooler, and it smells like moldering leaves in the morning. Similarly, we usually have a day in February that feels like spring - it's too warm for the heater in the truck and it smells like fresh grass.
I love the turning of the year. We're so lucky to live in place with distinct seasons. I enjoy each season, but I enjoy the change from one season to the next even more!