There are many cloud types which include: * cumulonimbus (thunderheads): near ground level to above 50,000 feet. * cirrostratus: above 18,000 feet. * cirrus: above 18,000 feet. * cirrocumulus: above 18,000 feet * altostratus: 6,000-20,000 feet * cumulus (fair weather): below 6,000 feet * stratus: below 6,000 feet.