Who knows that the sunshine in the bay will not rain?

It is sunny at noon, but it may not rain in the afternoon. If it rains, certain conditions are needed, depending on two means: one is the increase of condensation and condensation, and the other is the collision and increase of cloud droplets. In the initial stage of raindrop formation, cloud droplets mainly condense and condense themselves by constantly absorbing water vapor around the cloud. If the water vapor in the cloud can be continuously supplied and replenished, so that the surface of cloud droplets is often in a state of supersaturation, then this condensation process will continue, making cloud droplets grow and become raindrops. But sometimes the water vapor content in the cloud is limited, and in the same cloud, the water vapor is often in short supply, so it is impossible to make every cloud drop grow into a larger raindrop, and some smaller cloud drops have to be merged into larger ones. If there are water droplets and ice crystals in the cloud, the process of condensation and sublimation will be greatly accelerated. When the cloud drops increase to a certain extent, due to the increasing volume and weight of large cloud drops, they can not only catch up with the slower small cloud drops, but also "swallow" more small cloud drops, making themselves stronger. When the big cloud drops get bigger and bigger until the air can no longer hold them, they will fall straight from the clouds to the ground, which becomes ordinary rain.