chmur

Clouds are visible accumulations of tiny water droplets or ice crystals suspended in the Earth's atmosphere. They form when moist air rises and cools, causing water vapor to condense onto microscopic particles known as cloud condensation nuclei. Clouds influence the climate by reflecting sunlight and trapping heat, and they drive weather processes such as precipitation and storm development.

They vary in altitude, composition, and appearance, leading to a range of cloud types. High clouds consist mainly of ice crystals; middle clouds contain a mix; low clouds are typically water droplets. The microphysics involves nucleation, growth by collision and coalescence, and glaciation at higher altitudes.

Most common classification uses altitude and morphology: high clouds (cirrus, cirrostratus, cirrocumulus) above about 6,000 meters; middle clouds (altostratus, altocumulus) around 2,000–6,000 meters; low clouds (stratus, stratocumulus, cumulus) below about 2,000 meters; towering clouds include cumulonimbus.

Cumulonimbus clouds can produce thunderstorms with lightning and heavy rainfall; cirrus clouds can indicate an approaching front; stratus clouds may bring steady drizzle. Clouds influence solar radiation and visibility, and meteorologists track cloud type and height using satellite imagery, radar, and ceilometers.

In Polish, chmur is the genitive plural form of chmura, meaning "cloud," and is used in phrases such as kolory chmur (colors of clouds).