Science explained

Why leaves change colour in autumn

Many deciduous leaves change colour as plants respond to shorter days and seasonal conditions by breaking down chlorophyll and reallocating nutrients.

BiologyPlants

Editorial review: August 12, 2026 · Julian E. Marston

Chlorophyll dominates summer colour

It strongly reflects green wavelengths while supporting photosynthesis.

Chlorophyll declines in autumn

As it is dismantled, yellow and orange carotenoid pigments become more visible.

Some leaves produce anthocyanins

These pigments can add red and purple colours under certain conditions.

Weather affects the display

Temperature, light and moisture influence timing and pigment development.

This page explains scientific concepts for general learning. It does not replace laboratory safety procedures, professional engineering guidance, or individualized medical advice.