From the point of view of circulation, the state of water droplets on the surface of solid or liquid can be considered. If the surface tension of the other phase is small, the tension of water is relatively too large to penetrate. Because this circular water phase does not need to overcome gravity and air resistance, as long as no energy enters the disturbance, the water phase interface can be infinite. However, the surface tension of water can't support its own weight, and the water will disperse and become bigger, releasing energy. The actual case can be seen in Rain on the Lotus Leaf.
If spherical water droplets are formed under natural conditions, only rainwater can be considered. Rain is condensed from gaseous water in the sky. This process requires condensation of nuclei. If there are few nuclei and only a few water droplets are formed, but the temperature is not enough to directly turn gaseous water into solid hail and snow, relatively large raindrops may be produced.
Because gravity needs to be overcome at high altitude, the acceleration of gravity brings energy. When the surface free energy is too large and exceeds the tension constraint value, it will disperse into too many water droplets, and the obtained energy will be released by increasing the specific surface area.
If there happens to be an updraft, it can help water droplets overcome gravity. Or in microgravity and zero gravity environment, such as in the space station, this water drop can still be infinite without external force.
Exclude two extreme cases and only consider raindrops. Under the action of gravity, the final raindrop speed should be 10 meter, which is obtained by comparing the force generated by the surface tension maintaining ball with the force generated by the speed.