Fall colors
Why leaves change color in fall: the colors behind the green
Leaves change color as the green pigment chlorophyll breaks down during autumn. Yellow and orange pigments become easier to see, while some leaves produce red pigments. The mix varies by species and conditions.
What makes the different colors?
Chlorophyll supports photosynthesis and gives growing leaves their familiar green appearance. As deciduous trees prepare for winter, chlorophyll production slows and the existing green pigment breaks down. Shortening days are part of the seasonal signal.
Yellow and orange pigments that were masked by green become visible. Red and purple colors involve anthocyanins, which some leaves produce in autumn. A leaf’s final appearance depends on its pigments and how the season unfolds, so not every tree passes through the same sequence.
| What you notice | What is happening |
|---|---|
| Green fading | Chlorophyll is breaking down. |
| Yellow or orange | Other pigments become more visible. |
| Red or purple | Anthocyanins can contribute to the color. |
| A mix on one tree | Individual leaves do not all change together. |
Why the display varies each year
Weather influences autumn color and how long leaves stay on the tree. The National Park Service describes how sunlight and cool nights can favor red coloration in some species. A calendar gives a seasonal starting point, not a complete description of the trees along a particular trail.
For planning, separate three questions: have leaves begun changing, is much of the canopy colorful, and are those leaves still attached? A location can move through those stages differently from another place only a short drive away.
Try a repeat walk
Choose three trees along a route you already use. Mark their locations in your own notes and return every few days. You do not need to identify every species to notice differences, though a reliable local tree guide can make the exercise more interesting.
- Photograph each tree from roughly the same position.
- Record the date and whether most leaves are green, mixed, colorful, or fallen.
- Look at both the canopy and the ground.
- Compare the sequence after two or three visits instead of deciding the season from a single photograph.
This gives you an observation record for a place you know. Keep it distinct from a regional forecast: your three trees are useful evidence for that walk, but they do not represent an entire county.
Use the science to read a fall map
Next Light’s fall color map shows experimental estimates where data are available. Historical vegetation change and the most colorful day are different concepts. Read the date and coverage information before using a map to choose a trip.
If you are planning a visit, pair the map with recent local observations. Our fall timing guide explains how to compare a seasonal window, current reports, and a flexible route without treating one predicted date as certain.