Waiting around for the leaves to change? You’ll be waiting a while longer!

Leaves still green at your house?  There’s a good reason for that!  It’s mid-October, and despite what you might think should be happening, it’s not quite time for the blast of Fall color in North Alabama and Southern Tennessee just yet!

The peak of ‘Fall Color’ season begins around Halloween and goes through the first week of November; the color peaks in the mountains first, and then the colors become more vibrant westward across the Tennessee Valley as the days pass.


Why do leaves change colors in the fall?

Up close view of a leaf. (Getty Images)

From spring into summertime, a compound located within the leaves allows trees and other plants to produce food.

This compound, known as chlorophyll, reacts with sunshine as well as carbon dioxide to create glucose, a type of sugar that serves as the plants’ energy source.

Plant cell with chloroplast/chlorophyll under a microscope. (Getty Images)

Chlorophyll is the color green, and so much of it is produced in the spring and summer that the overwhelming color from trees and plants is the ubiquitous shade of green.

In the fall, the decreasing amount of daylight as well as changing solar angle signal to the trees and plants that winter is coming. Leaves contain a great amount of water content, and if these were to freeze during the winter, it would cause a large amount of stress to the plant.

That’s why trees and plants gradually stop production of chlorophyll and divert water resources from the leaves to the trunk or branches. As the chlorophyll fades away, other compounds present in the leaves produce the vibrant colors that we see every autumn.

As the leaves become sufficiently dry, they are no longer able to remain attached to the tree or plant, and they fall to the ground.

What factors influence the brilliance of the colors?

According to the University of Tennessee Institute of Agriculture in a 2012 article (linked here): “past weather conditions indicate trends for what we might expect.”

  • ‘Warm, dry weather with extended droughts or moisture deficits yields color that is not as vibrant, is short lived (a week or so), and the timing can be delayed a week or more.’

  • ‘Adequate moisture yields a longer period of leaf color.’  (Normal or above-normal rainfall leading up to the change)

  • ‘Sunny days create more vibrant leaf color. Leaf color is less vibrant (more dull) with several rainy or overcast days in a row when leaves are turning color.’

  • ‘Cool nights with temperatures in the 40s and low 50s (but not freezing) with daytime highs in the 60s and 70s tend to retain leaf color longer, and the colors are more pronounced, especially if the days are sunny.’

  • ‘Freezing overnight temperatures and early frost: show’s over. Leaves will turn brown and die.’

Looking for the forecast? It’s always online at WHNT.com/Weather and in the “Daily Forecast” section on Live Alert 19!

If you get great photos of Fall, pumpkin patches, or other cool weather shots, share them with us!  You can upload with Live Alert 19 or submit your photo with the button at the bottom of this article.

-Jason
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