How Will the Drought Affect Fall Colors?

Many articles have been written on predicting the best weather for beautiful fall colors across Wisconsin.    Several inquiries have been received asking if the general lack of rainfall and drought conditions across south east and south central Wisconsin will influence the fall colors, and the answer is maybe. Some species of deciduous trees may drop their leaves before the fall color process can begin. Other consequences are a less colorful or drab intensity in some other species.
Timing of the color change is controlled primarily by the calendar because the increase in the length of night is one of the primary triggers. The amount of soil moisture is important and will affect the amount of sugar production in the leaf cells.

Drier than normal weather in the late summer into early fall will tend to accelerate the leaf changing process causing leaves to fall prematurely. A warm period during the fall will also lower the intensity of the autumn colors.

A wet September and October will tend to produce less vivid colors and leaves may also drop earlier due to the wind, rain and storms.

The best fall colors are experienced when there is a warm, wet spring, “normal” summer weather followed by a long period of warm sunny days and cool crisp nights with temperatures remaining above freezing in the fall.

These sharp daily temperature swings and more importantly, the decrease in sunlight, play vital roles in the development of the leaf color.

For a more in depth explanation of why leaves change color, go to the US Forest Service website at:

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