Typically, as the days get colder and shorter during autumn, leaves are exposed to less sunlight. This slows down the production of chlorophyll, which helps plants create their own food through photosynthesis and gives them a natural green color. With less food fueling their sun-powered diet, that green is replaced with other primary colors.

Warmer nights and a lingering drought in our region are among the climate change items that are impacting fall foliage and the change in leaf colors.

During the summer, leaves appear green because the predominant pigment of photosynthesis, called chlorophyll, reflects green light. But chlorophyll is full of nitrogen and other valuable components, so when they can, trees will pull the pigment out of their leaves as winter approaches.

Weather patterns can brighten or dampen fall colors, but it is something inside the leaf that determines the coloring.

A professor of biological sciences at the University of Wisconsin–Milwaukee explains that changing leaves starts with environmental cues, like days getting shorter and chillier.

In our latest Beyond the Forecast special on WPRI.com, 12 News Meteorologists Steven Matregrano and Catie McNeil talked all about autumn, breaking down the forecast for fall 2024 and answering

But why do leaves change color in the first place? And what determines the color a leaf will change? Foliage Forecaster Jim Salge explains that the trees are responding to changes in light and temperature.