The Return of Nature’s Most Colorful Show – Fall Colors Foliage Forecast
Whether it started on September 1st, or will start on September 23rd, the autumn season delivers one of nature’s most brilliant displays.
Fall foliage draws many tourists to nearby parks and forests, but many don’t know the science behind why leaves change color or the role that weather plays in creating fall’s brilliant colors.
The U.S. Department of Agriculture notes that the colors in a tree’s leaves come from a combination of chlorophyll, carotenoids (which give leaves a yellow, orange or brown color), and anthocyanins (providing the shades of red). The mixture of these chemicals inside a tree’s leaves can change based upon the weather from the period of time just before the color change. A series of warm days and cold (but not freezing) nights will bring out the most vibrant colors. The color change occurs when the shortening days leads to less intense sunlight, which prompts the tree to seal off vital sugars from leaves.
As with most things, timing is critical. To bring about the most vibrant foliage, the shortening days have to occur during a period of just-perfect weather. Because the timing of leaf fall is tied to the amount of sunlight, the peak intensity of the foliage can usually be pinned down to a couple of weeks in September, October, or November. The intensity of the show is truly out of our hands. The attached map can tell you when to see the fall foliage – but not how vibrant it will be.
For WeatherNation: Meteorologist, Jason Cerjak
(Post Image courtesy of the National Park Service)