What is the origin of "the louder the frog, the more the rain"?

Question

I would like to know where this saying came from, what it means and how accurate it is.

Answer 1

It is a basic proverb, common in many cultures, lands.

The Roman Virgil names the frogs as one of his sure weather signs for rain, croaking away ‘at their old complaint' Theophrastus says that " frogs croaking more than usual indicate rain. So ancient Greece as well.

"When frogs warble, they herald rain" (Zuni Indians).
The louder the frogs, the more's the rain". "The color of a frog changing from yellow to reddish indicates rain".
The frog croaking more than usual is a harbinger of rain (Ael. 9.13)
A croaking frog is a good sign of rain. They croak louder if a storm approaches

James Macauley - 1829
The croaking is louder in the evenings on the approach of rain

Graham's American Monthly Magazine of Literature, Art, and Fashion
by Ann Sophia Stephens, Rufus Wilmot Griswold, Edgar Allan Poe, George R. Graham - 1855
... which told him, beyond a doubt, that there would be rain on the morrow, and that, a halo surrounded the sun; the tree-frog sang louder than ever; ...

frogs are called " Cambridgeshire nightingales."
At night, and especially before rain, the frogs make a tremendous croaking 1902

superstitiously believed in Bengal that the croaking of frogs
prognosticates the failing of rain

Answer 2

it comes from Native Americans who would predict the rainfall by how loud the animals were