What Fall Colors Mean

As the days turn longer, less sunlight means less oxygen and glucose for plants and leaves and ultimately less chlorophyll, which hides the reds, yellows and oranges. Different materials cause different colors in leaves. Red comes from glucose, brown from waste and purple from anthocyanin. Yellow is always present in leaves, but during spring and summer, the green overpowers it.

The timetable for leaf transformation runs from September through early November. Typically, the first to see breathtaking fall foliage are the Rockies, Upper Midwest, and New England. From there leaves begin to change further south into the Ohio Valley, Pacific Northwest, and Middle Atlantic toward mid and late October.

The first frost and time of leaf change typically go hand in hand. Within a week or so of the first frost, expect quick leaf transformation. Other factors such as the amount of water during the summer and early fall impact the full potential of color. More water means better color.