What is Precipitation and How do Clouds Form

Clouds and rain are a fascination of many from a young age. I’m sure we’ve all looked out of the window at one point or another and wondered how these clouds come into existence. Wondering about these floating mysteries is common. We’ve also spent hours trying to deduce how it rained when we were kids.

Where does the water come from? How does it snow? These are all some of the common questions among highly inquisitive children. Today we’re going to answer some of those questions.

what is precipitation and how do clouds form

What is Cloud?

what is cloud

Condensed water vapor in the sky, which is in the form of very tiny water droplets or ice crystals that look like shapes or formations from the ground level is called as Cloud. 

How are Clouds Formed?

Though air everywhere contains water, air near the ground usually has a high amount of water in the form of water vapor, which expands and cools. 

A certain amount of water vapor is always present in the atmosphere, and when the water vapor crosses the threshold limit, exceeding the value of invisible water vapor that the atmosphere can hold, clouds are formed.

how clouds formed

Clouds are not heavy, but they are suspended in the air as the very small dust particles stick to air. Warm air is capable of holding more water vapor than cooler air. Due to this factor, if lots of water vapor is present in warm air, a cloud is generally formed when the water inside cools.

This vapor condenses into tiny pieces that are floating in the air, and billions of these droplets accumulate together before they are a visible cloud. The different ways in which warm air can be cooled to form clouds are:

  • When the air near the ground rises to where the air is cooler after being heated by the sun.
  • Warm air is cooled down when it passes through cold air along weather fronts.
  • Air cools as it goes higher up on the side of a mountain. 
  • After passing through something colder, like cool water in a lake, or ground at night, warm air is cooled. 

Cooling of Clouds:

Cooling of clouds occurs in many different ways:

  • Deep layers of clouds are formed by the action of air rising along the warm front, and it’s subsequent cooling. This may occur near ground level on a few occasions.
  • Cold fronts cause air to rise to lead to a wedge of dense and cold air pushing through the moist air surrounding and lifts the warm air.

Clouds are vital factors influencing and controlling the Earth’s weather, climate, and atmospheric conditions. The temperature, wind, and other conditions present during the formation of a cloud decide what kind of Cloud is formed. 

Types of Clouds

Clouds are generally classified according to two different aspects called location and shape. The exact height of the Cloud varies according to the temperature during formation, but high clouds are formed several kilometers high in the sky while low clouds are formed within a kilometer or two of the Earth’s surface.

If the clouds are formed at a very low level, almost touching the ground, it is called fog. Low level and high-level clouds are separated by middle-level clouds. 

Cirrus Clouds: 

They are thin and wispy, which results in them often curving with the wind.

Cumulus clouds: 

They resemble the shape of giant cotton balls, taking up different shapes in the sky. They are middle-level clouds which are big and fluffy, forming parallel stripes of clouds. 

Stratus clouds: 

They form different sheets covering a large area of the sky in the form of sheets. 

What is Precipitation?

Liquid or frozen water that is formed in the atmosphere to fall back to the surface of the Earth is called as precipitation. Precipitation has various forms like rain, sleet, snow, etc. It is one of the important steps of the global water cycle in addition to evaporation and condensation. 

How is Precipitation Formed?

When condensation of water vapor in clouds turns into bigger size, droplets occur and precipitation is formed.

what is precipitation

These drops fall to the Earth’s surface once they are heavy enough. In higher altitudes, where the temperature is very cold, water droplets freeze to form ice crystals that fall to the surface in the form of snow, hail, rain, etc. according to the temperature near the Cloud and Earth’s surface.

An interesting fact is that almost all rainfall begins as snow at the high altitude of clouds but become raindrops as they pass through the warm air. 

Dust and smoke particles in the atmosphere aid precipitation and are called “condensation nuclei” as they provide the surface area for condensation of water vapor where the droplets gather together till they are large enough to fall to the Earth.

Composition of Precipitation

Rainwater is always fresh water, even when it is formed by evaporation of ocean or marine water as sea salt does not evaporate along with water. In rare cases, pollutants can contaminate precipitation before they reach ground levels, and this is called as acid rain.

Though acid rain isn’t directly harmful, it causes lakes and streams to become highly acidic, harming ecosystems as plants and animals cannot adapt to the high acidity levels.

What Causes Rain?

what causes rain

Water present in the clouds is usually in the form of very small droplets, but these droplets have the ability to collect more water to turn into larger drops. Once more water is collected, increasing the size of the droplets, gravity acts on it, causing it to fall through the air at a faster pace.

These falling droplets are nothing but rain. Snowflakes are formed by water when the temperature is very cold, and clouds can freeze to cause freezing rain or sleet as well, which occurs when the snow melts while falling to the ground but quickly gets colder or frozen again.

Hail fall occurs during extreme or severe weather conditions, and it is caused when bigger chunks of ice fall to the ground. Air current is the driving force behind the movement of rain and snow around the sky. 

Difference between Rain and Drizzle

As cloudy skies arise with long durations of rain, snow, and drizzle due to changing weather fronts during chilly conditions, the air is forced to rise as it gets convected by heat in the Earth’s surface.

The major difference between rain and drizzle is the size of its droplets. Drizzle consists of extremely tiny droplets less than half a millimeter that merges together until it’s heavy enough to fall from the clouds by the action of gravity. Also, check our recommended rain gauge devices to measure different kinds of rainfall.

  • FAQ

Some Frequently Asked Questions About Cloud and Precipitation

Why are clouds white?

Light travels in the form of waves with varying lengths, and each color is specific to its own unique wavelength. The water droplets or crystals of ice are large enough to scatter light of all the seven wavelengths red, orange, yellow, green, blue, indigo, and violet the amalgamation of which white light is formed. This is why clouds are white. 

Few times, clouds exhibit different unique colors at sunrise or sunset by the influence of dust particles in the air. 

Why do clouds turn grey? 

Clouds are a mixture of ice crystals and water droplets that scatter all light giving a white appearance to clouds. When the clouds get thicker or higher, enough light doesn’t pass through the Cloud giving it a greyish tinge. A grey look may also occur due to the shadow cast by a number of clouds nearby. 

Why do clouds float?

A cloud is made up of liquid water droplets. A cloud forms when air is heated by the sun. As it rises, it slowly cools it reaches the saturation point, and water condenses, forming a cloud. As long as the Cloud and the air that it is made of warmer than the outside air around it, it floats!

How do clouds move?

The wind drives around or moves clouds in different directions. Cirrus Clouds, which are high levels clouds are often pushed by jet streams, traveling more than 100 miles per hour. Clouds taking part in thunderstorms move at around 30-40 kilometers per hour. 

Why do clouds form at different heights in the atmosphere?

The different elements nearby like the amount of water vapor, the temperature at the height of formation or location, the wind, the influence of other air masses decide various aspects of the Cloud, including the height of the formation. 

Why are clouds important? 

Clouds are very important for a lot of reasons. Precipitation, like rain or snow, responsible for distribution and redistribution of freshwater on the Earth’s surface, is a major factor highlighting the importance of clouds. Clouds reflect heat back to the surface to keep warmer temperatures during the night and serve as shade to keep us cooler during the day. Satellites in space help us study clouds. 

What is water cycle?

When water on the Earth evaporates and rises higher into the sky in the presence of colder air, these gas drops change from gas forms and condense into water droplets or crystals of ice. This is visible to us as clouds. The drops and crystals fall to the Earth in the form of rain or snow before evaporation occurs one again. This is called as water cycle. It is a cycle responsible for the distribution of water throughout the Earth’s surface. 

How do raindrops appear? 

Smaller raindrops are spherical in shape instead of teardrop-like as they are generally represented. Larger raindrops are usually round with a small indent at the bottom of the drop, looking like kidney beans. Very large drops have a huge indent and look like parachutes, which ultimately splits to form two small drops. These indents on the raindrops are caused by air resistance. 

How are snowflakes formed?

Ice crystals undergo rapid cooling in the presence of supercooled water nearby and cause the crystals to drift through clouds. Here crystals connect with one another in a process called aggregation, and snowflakes are formed. Aggregation can take place in all clouds irrespective of whether it’s near the waterfront. 

Snowflakes melt and fall as rain on the surface when the conditions are warmer. Almost all rainfall originates as snow but melts before reaching the ground.  


So the next time it rains or the day is a bit cloudy, you know the whole story behind the conditions of the skies after going through this piece so you’ll never be clueless again, regarding this aspect!

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About the Author


I am Tim, a weather enthusiast who loves to watch hurricanes and all other harsh weather conditions. I studied B.Sc(Meteorology) at the University of Miami. With excellent knowledge of Weather Forecasting, Meteorology, and Environmental Science, I am currently working in San Francisco as a Meteorologist. Also, I am a member of The Weather Channel and AccuWeather. In this blog, I will write a detailed review of Weather instruments that you need for survival and other activities.