Cumulus clouds mostly form as a result of localized pockets of warm air rising.
Cumulus humilis is the smallest form of cumulus clouds and results from relatively weak convection (humilis means humble in Latin). This produces clouds that generally have flat bases and small, rounded tops. Technically, a cumulus cloud is considered to be a humilis formation if it is wider than it is tall, as estimated by an observer on the ground. The height of these type of clouds is about 500 tot 1000 meter or 2000 to 3500 feet. It’s unusual that rain falls out of these type of clouds.
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