Behind the Forecast: Can leaves predict the weather?

LOUISVILLE, Ky. (WAVE) - There are many old wives’ tales about the weather. There is some truth to the stories of a tree’s leaves flipping over as a sign of rain.

Deciduous trees, like maple, oaks, and poplars, are sensitive to humidity. The leaves of these trees (with soft stems) sometimes become limp and pliable due to abrupt humidity increases ahead of the rain, letting the wind flip them over and turn them upward. Gusty winds are typical before showers and thunderstorms (especially in the summer), which can cause leaves to flip over and show their underside.

This change is not a long-range forecast. It is usually a sign that rain is not too far away.

Pine cones are excellent forecasters. They open up during dry conditions, as the outer part of the pine cone’s scales dry. During more humid and damp conditions, a pine cone becomes more flexible and closes (returning it to its typical shape).

You can smell the oncoming rain. When water hits various surfaces, it displaces odor molecules (like plant compounds and pushes them into the air (think bubbles in Champagne). The smell of rain is called petrichor. This smell is most noticeable after warm, dry spells, which allow these compounds to accumulate; more is released during that first round of rain.

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