I can toss a feather into the air and on a quiet day it will settle to earth. Yet at times when I look up at dark storm clouds that must be carrying tons of water, the water does not fall. Why? I can understand the power of updrafts in thunderclouds that keeps water aloft, but I am talking about ordinary rain clouds.
-- John Coult, Chicago
All cloud particles, from the largest water drops to the most miniscule droplets, respond to the pull of the Earth's gravity and fall. They remain aloft only because they exist in an environment of rising air. The surging updrafts of powerful thunderstorms, frequently exceeding 60 mph, are an obvious example, but even the misty droplets of fog or the droplets comprising the gray overcast of a layer of stratus clouds fall, albeit very slowly. An average-sized cloud droplet descends at a speed of less than 2 feet per minute (about 0.02 mph).