Underside of leaves when it rains?

Question

My grandpa always told me that you can tell it's going to rain when you can see the underside of the leaves. This has always seemed to work so is there a scientific source behind it? It can't just be the wind, could it?

Answer 1

    i think your gramps is right.i dont understand it.but it does happen.

Answer 2

i think it is only a coincidence,,,,,..but i'll try to stare them when i have a leisure time..But for now, i will consider it as a superstitious belief...

Answer 3

It is the result of wind-shear.  Often, as a cold front approaches, the wind will suddenly change direction and velocity.  This will cause the leaves to quickly change the direction they are facing. Cold Front often bring rain.  So, yes, it is just the wind.

*