For millennia, humans have looked to the sky to tell the future. Clouds gave warnings of incoming weather and temperature changes. Although modern people rely more on the weatherman and less on their own observations, knowing the different types of clouds can make the difference between a fun hike in the mountains and getting drenched in a storm. Use these guidelines to learn more about clouds and the weather.
Identify the cloud by determining its shape. This will also give you an indication of its altitude. For example, "cotton ball" clouds, correctly called cumulus clouds, form at low altitudes. Stratus (layer) clouds at low altitudes look like fog, while stratus clouds at middle altitudes take on a more distinct shape. High-altitude clouds appear wispy and translucent.
Pay attention to cumulus clouds that appear to grow taller and whose height equals or exceeds their width. These are cumulus congestus clouds and they frequently bring rain showers.
Scan for anvil-shaped heads on tall cumulus clouds. These are called cumulonimbus clouds. The anvil head occurs when the top of the cloud bumps against the tropopause layer of Earth's atmosphere. These giant clouds often produce violent summer thunderstorms and may give rise to tornadoes.
Look higher in the sky to find altostratus clouds. These clouds form at middle altitudes and appear thick and uniform. You can almost always determine the position of the sun through a layer of altostratus. Generally gray, these clouds often bring rain.
Stay indoors when you see nimbostratus clouds. Another middle altitude cloud, these thick, dark-layer clouds completely block the sun. They give rise to continuous, persistent precipitation.
Distinguish altocumulus clouds by their patchy appearance. Colloquially described as "mackerel scales," these middle altitude clouds often give advance warning of stormy weather in the near future.
Peer high in the sky to find cirrus clouds, a high altitude type of cloud. Also known as "mares' tails," these clouds appear as thin, curvy wisps and often precede precipitation.
Recognize cirrostratus, a thin upper-level layer cloud, by the halo effect it produces around the sun and moon. Made of ice crystals, they serve as an early harbinger of deteriorating weather conditions. The sun can always shine through cirrostratus clouds.