
A visible mass of water droplets or ice crystals suspended in the atmosphere.A cloud is a visible suspension of tiny water droplets or ice crystals in the atmosphere, formed when moist air rises, cools, and reaches saturation. Clouds are central to Earth's weather and climate, regulating the planet's energy balance by reflecting sunlight and trapping heat. They also drive the water cycle, delivering precipitation that sustains life, and their behavior is a key factor in predicting storms and long-term climate change.
The modern understanding of cloud formation began in the 19th century with Luke Howard's classification of cloud types (1802) and later advances in thermodynamics by scientists like Hermann von Helmholtz.
Clouds form when air containing water vapor rises and cools adiabatically, causing the vapor to condense onto microscopic aerosol particles called cloud condensation nuclei. As millions of droplets collide and coalesce, they grow heavy enough to fall as rain or snow. The exact processes of droplet growth and turbulence within clouds are complex and actively studied, as they determine whether a cloud produces light drizzle or intense downpours.
Cloud physics informs weather forecasting, climate modeling, and cloud-seeding techniques used to enhance precipitation in arid regions.
A single cumulus cloud can weigh over a million pounds, yet it floats because its density is only slightly greater than the surrounding air, and the updrafts keep it aloft.










