How it works
Green chlorophyll dominates during the growing season. As trees prepare for winter and seal off leaves, chlorophyll breaks down and other colors become visible.
What people often miss
Weather, tree species, moisture, and timing affect the display. Frost, drought, or storms can shorten or dull the season.
Why this question comes up
The timing and intensity of fall color vary widely from year to year.
Key points
- Shorter days and cooler conditions slow chlorophyll production, revealing yellow and orange pigments already present while some trees produce red pigments.
- Green chlorophyll dominates during the growing season. As trees prepare for winter and seal off leaves, chlorophyll breaks down and other colors become visible.
- Weather, tree species, moisture, and timing affect the display. Frost, drought, or storms can shorten or dull the season.
Bottom line
Shorter days and cooler conditions slow chlorophyll production, revealing yellow and orange pigments already present while some trees produce red pigments.
Source and verification
This Answer was checked against USDA Forest Service: Fall Colors. Follow the source for the full official explanation and any later updates.