The Sun's heat is responsible for the creation of wind, clouds and rain, and different sorts of weather on the planet.
Almost everyone watches clouds, among the most fascinating and easily observed of all weather phenomena. Clouds form through the process of condensation when water vapor, primarily from the oceans, rises into the atmosphere where it cools and condenses into cloud formations. If the condensed droplets in a cloud get large enough, they’ll fall as precipitation. Rain clouds, or nimbus, produce everything from drizzle to downpours; more violent relatives of theirs may unleash rain as part of intense thunderstorms.
TL;DR (Too Long; Didn't Read)
Rain or "nimbus" clouds may appear as low, sheeted "stratonimbus" producing sprinkles or steady drizzle or as tall "cumulonimbus" clattering with thunder and flashing with lightning. The cumulonimbus's forerunner, cumulus congestus, may also drop rain.
Nimbus Clouds
Nimbus is an ancient Latin word meaning “rain storm.” Rain or nimbus clouds tend to appear dark gray because their depth and/or density of large water droplets obscures sunlight. Depending on temperature, nimbus clouds may precipitate hail or snow instead of liquid rain.
The prefix “nimbo-” or the suffix “-nimbus” designate two prominent kinds of rain clouds, "nimbostratus” and “cumulonimbus," although rain sometimes falls from other cloud varieties.
Cloud Classification
Understanding the two major varieties of rain cloud means knowing the basics of how meteorologists classify clouds. Besides being identified as precipitating nimbus or not, clouds are classified by their appearance – layered (“stratus”), heaped (“cumulus”) or a combination thereof – and by their altitude. Low-altitude clouds include stratus, cumulus and stratocumulus clouds. Mid-level clouds are designated with a prefix of “alto-” and include altocumulus and altostratus clouds. The highest altitude clouds, which appear wispy and feathery, are called cirrus clouds and include cirrocumulus, cirrostratus and cirrus clouds.