The maximum radius for cloud droplets is about 0.05 millimeters. However, typical raindrops have volumes thousands of times greater. Let's examine how these tiny cloud droplets turn into raindrops. Forming raindrops occurs within cumulus (cumulonimbus) and stratus (nimbostratus) clouds via the Bergeron process or the collision-coalescence process. The Bergeron process is active at subfreezing temperatures. Ice crystals grow from supercooled water dropletstiny water droplets that are liquid below the freezing point of water. If a cloud is saturated with water, it is supersaturated with ice. Therefore, as ice crystals form, water droplets evaporate to replenish the water vapor used in forming ice crystals. These ice crystals can grow large enough to fall to the ground, melting to form raindrops as they reach higher temperatures during decent. For the collision-coalescence process: Larger water droplets collide and join with other water droplets, eventually forming raindrops that are large and heavy enough to fall to the ground. When these water droplets have more of an opportunity to collide with other water droplets (e.g., in taller clouds or because of updrafts), they are better able to form raindrops. Additionally, because the droplets are not all exactly the same size, they will move at different