Whether it's beautiful red and yellow leaves falling during the autumn months, or a ripened fruit dropping from a tree, this natural process is called abscission.

In the fall, as days shorten and temperatures cool, trees begin to seal off the connection between their leaves and branches at a specialized layer of cells called the abscission zone.

This layer gradually weakens, allowing leaves to detach and fall once they’ve finished their seasonal work of photosynthesis. It’s the tree’s way of conserving energy and protecting itself through the colder, less sunny months.

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This process is also what gives us the brilliant colors of autumn. Before a leaf drops, the tree stops sending it nutrients, and the green chlorophyll fades away.

What’s left behind are yellows, oranges and reds from pigments that were hidden all summer. Abscission doesn’t just create fall foliage; it’s also a survival strategy, preventing trees from losing too much water or suffering damage from snow and ice weighing down their leaves.

But while abscission is a biological process, it’s shaped by weather conditions each year. Cool nights and warm, sunny days tend to produce the brightest colors and a slower, more vibrant transition.

Early frosts can cut the process short, leading to quick leaf drop with muted colors. Drought stress may trigger abscission weeks early as trees conserve water, while strong autumn storms and winds can strip branches before the leaves are ready.

That’s why no two fall seasons ever look exactly alike — the weather plays a huge role in how and when the final leaves fall.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.