There are many different types of clouds. High clouds are cirrocumulus, cirrus, and cirrostratus. Middle clouds are altostratus or altocumulus. Low clouds are cumulus, cumulus humilis, cumulus mediocris, stratocumulus, nimbostratus, and stratus. Vertical clouds are cumulonimbus, cumulonimbus calvus, cumulonimbus incus, cumulonimbus with mammatus, cumulus, cumulus congestus, and pyrocumulus. There are also noctilucent and polar stratospheric clouds.