The arrival of autumn always bring a spectacular sight. The changing of the leaves from green to red, gold, yellow, orange and other hues brings out leaf peepers from all over.

In Maryland, the change usually begins in Garrett County, and then spreads east, eventually reaching Frederick County and surrounding jurisdictions.

While the colors are a feast for the eyes, there's a scientific process for this changeover. "A lot of it has to do with the length of the day," says Jack Perdue, Program Manager for Forest Resource Planning for the Department of Natural Resources. "When the days start to get shorter, the trees start to respond to that and cut circulation to the leaves."

In fact, Perdue says, the colors that you see in the autumn are already inside of the leaves. "In the base of the leaf, there's a little, almost like a valve, that when those things are triggered, it starts to cut off the sugars that are flowing to the leaf," he says. "And when that happens, it restrict the flow of chlorophyll." That unveils the colors already inside the leaf.

This process usually begins in October, but a lot of the trees in the Frederick area started to turn in September. "But you get some cold spots in certain areas, like in Frederick County, then those areas might start to change a little bit sooner, like in higher elevations," Perdue says.

Frederick County experienced some cool weather during September, as well as some rain.

This autumn color show usually takes place in October, and in November, the leaves start turning brown and falling off. So Perdue says catch this free spectacle from Mother Nature while you can. "It may be gone real quick. You may get a storm that comes through, and knocks all the leaves off. A heavy rain knocks those brilliant leaves off and the opportunity is gone," he says. That is, at least until next fall.