CLARKSBURG, W.Va. (WBOY) — Last week, the West Virginia Department of Tourism announced that 2022’s fall foliage is the best that the state has seen in 10 years. But why is that?

According to the United States Forestry Service, scientists have worked for years to understand the changes that occur in trees and shrubs that lead to fall colors, but still don’t know all the details.

As days grow shorter, and nights grow longer and cooler, the green pigments in leaves, called chlorophyll, are not produced as quickly as they are when there is more sunlight each day. Plants eventually stop producing it altogether, meaning the leaves’ red, orange and yellow pigments show through instead.

The Forestry Service said weather conditions that occur during this point where the chlorophyll is dwindling does seem to influence the brightness of fall foliage, especially temperature and moisture.

The most spectacular colors, it said, seem to pop after a succession of warm, sunny days and cool, crisp but not freezing nights because lots of colorful red pigments are produced, but the cool, not cold nights, make it harder for the pigments to escape the leaves’ veins.

Yellow and orange pigments are produced more evenly, the Forestry Service said, which is why they vary less year to year than shades of red.

The Forestry Service said a late spring or bad summer drought can delay the onset of fall color by a few weeks and a warm period during fall will lower the intensity of autumn colors.

So, the Forestry Service said, the most favorable conditions for a beautiful fall are a warm wet spring, favorable summer weather, and warm sunny fall days with cool nights.