Windy limerick

It means: when there are no dark clouds in the sky, it rains heavily, but when the treetops are still, the wind blows heavily.

"There is no cloud in the sky and it rains heavily, but the treetops are still and the wind blows" is an irony. It means that when there is no cloud in the sky, it rains heavily, but when the treetops are still, the wind blows heavily. When there are no dark clouds in the sky, but it rains heavily, it is usually caused by the difference of air pressure and temperature at high altitude; When the treetops did not move, there was a strong wind, which was probably caused by the change of wind direction in the distance. This sentence tells us that sometimes natural phenomena are not as simple as what we see with our naked eyes and need to be understood and analyzed from more angles.