The nature of the occurrence of rain. Why does it rain - where does it come from? Why is it raining heavily

Children are very inquisitive. They hope to always receive comprehensive answers to their many questions from adults.

When a child sees rain, on the street, in a picture or in a cartoon, he may have a question: Why is it raining? Where does it come from in the clouds? How is it formed? Why does it fall from the sky?

Rain is one of the stages of the water cycle in nature. When the Sun shines on the Earth, it warms it up. There are many different bodies of water on our planet - rivers, lakes, seas and oceans. The light and warmth of the sun heats all this water. Some of the water becomes steam. These are very small droplets of water that are difficult to see individually.

We see it when water boils in a saucepan or kettle. The steam is very light, which is why it rises into the sky. When there are a lot of small droplets of steam, clouds are formed that float in the sky, high above our heads. They are driven by the wind.

While the air is warm, nothing happens to them. But when the air gets cold, small droplets of steam are attracted to each other and become larger raindrops.

Gradually the clouds become heavy and large. And then they rain down on the Earth.

How to make rain with your own hands?

You can demonstrate a simple experiment to your child at home. To do this, put a pan of water on the fire. Hold the lid over the pan. To keep it constantly cold, place pieces of ice on top. As the water heats up, steam will form. It will rise and settle on the bottom of the lid. The steam droplets will begin to connect. The child will then see large droplets of water dripping back into the pan. This is how you get artificial rain at home.

St. Petersburg is considered the cultural capital of Russia, attracting millions of tourists every year. This place is not like an ordinary resort town, because it can change several times a day, and rain prevails here, regardless of the time of year.

Reasons for rainy weather in St. Petersburg

It often rains in St. Petersburg due to the unique geographical location of the city. When Peter I was just planning to “cut a window to Europe,” he conceived the construction of a huge capital on the shores of the Gulf of Finland.

To do this, they drained swamps and fought floods. Even when the tsar was shown traces on the trees from the last flooding of these places, he did not change his decision, erecting the Peter and Paul Fortress on Hare Island.

It's no secret that St. Petersburg is a “city in the swamps.” Due to the constant high humidity, its streets are often shrouded in fog. The northern capital is located next to numerous bodies of water - the Neva, the Gulf of Finland, and lakes. Constant evaporation envelops the populated area in thick, heavy clouds, preventing sunlight from entering.

The location of St. Petersburg has another feature. It was built at the intersection of numerous air masses from different regions. Most often, the western and northwestern wind blows here, which brings long-lasting cyclones from the Atlantic Ocean and the Baltic Sea. They cause rain.

There are rarely showers, thunderstorms, or hurricanes here. It walks steadily, it is constantly drizzling. Local residents have long been accustomed to this weather, but tourists may find it strange.

Watch an interesting video about the weather in St. Petersburg below:

It seems that there is a suspension of small drops in the air. You don’t want to open an umbrella in this weather, but after half an hour you find yourself completely wet.

If you are going to St. Petersburg, regardless of the time of year, take with you warm, waterproof shoes and a comfortable raincoat or windbreaker that does not allow moisture to pass through. In such clothes you will be comfortable exploring the sights of the great city.

Sometimes the westerly wind gives way to the north. Then it becomes clear but cool in St. Petersburg. A change in wind signals the approach of dust storms. Visitors who encounter such a cataclysm note that a small, permanent one is much more pleasant. the north wind brings noticeable frosts.

Temperatures may drop at this time up to -20 °C.

Warm, dry air blows less frequently from the east and south. It brings warming, but does not cancel the rains, they only become stronger. The weather in the city often changes several times a day. The sun is shining in the morning, but it is noticeably cool outside; by lunchtime a warm downpour begins, and in the evening it turns into a light but prolonged downpour.

Winter rain in St. Petersburg

Due to the climate and location of the city, it can even rain here. Thick, heavy clouds trap warm air, preventing it from rising into the upper atmosphere.

Temperatures remain above freezing, and when precipitation does occur, it comes in the form of rain rather than snow.

Despite the gloom and some grayness of the city, an amazing atmosphere reigns here, which is also formed due to weather conditions. And due to the abundance of precipitation, the first emerald green appears in the city. Tourists who come here for the first time note that they have never seen such richly green grass on lawns and foliage on trees anywhere else. This is also due to frequent rains.

The formation of rain is directly related to one of the key natural mechanisms of our planet - the water cycle. There are many rivers, seas and oceans on Earth, the water in which tends to evaporate.


This happens under the influence of sunlight: the sun heats the surface of the water, and the large drops of which it consists turn into tiny ones, forming light steam. It rises up and enters the atmosphere. Depending on the air temperature, a certain amount of moisture is retained in the atmosphere.

Gradually it condenses and clouds form in the sky. Not all of them become rainfall, but sooner or later the accumulated water in vapor or droplet form again enters reservoirs and land, from where it either penetrates underground and then again enters reservoirs in the form of groundwater, or again evaporates from the surface.

What happens inside the cloud?

Moisture in clouds can travel vast distances - it is supported by rising air currents. Drops of water fall to the ground only after they become large and heavy enough. Inside the cloud, the process of steam condensation continues: particles of steam from the air settle on the smallest drops of water.

Droplets inside the cloud move in different directions, collide with each other and connect with each other. But clouds are not only accumulations of a large number of water droplets, they are also a mass of tiny ice crystals. If there are only water droplets in the cloud, their enlargement occurs very slowly - one raindrop contains about a million of these tiny droplets of steam.


And if the cloud is mixed, then water droplets are in its lower part. And in the upper, in the region of colder air, those same ice crystals are concentrated in the cloud. Rain forms quite quickly in such a cloud. And sometimes it happens that warm air rises very quickly in summer, and at high altitudes, under the influence of negative temperatures, drops en masse turn into pieces of ice and fall to the ground in the form of hail, without having time to melt.

After it begins to rain, new streams of moist air replenish the rain cloud, and this continues until the flow of moisture weakens. In summer, every cubic kilometer of rain cloud can contain about a thousand tons of water. The largest rain clouds, from which real downpours will pour, form on hot days, when a large amount of evaporating moisture rises from the surface of the earth into the air.

The cloud grows, increases in size and gradually its top reaches the cold layers of air. At approximately eight thousand meters above the ground, the air temperature can be down to minus thirty degrees. It is at this extreme cold that drops of steam crystallize into ice.

Often, when we see a dark cloud, we think that now. But the darkest gray clouds can pass by without shedding a drop of moisture. A sure sign that a cloud is truly thunderstorm is its blue-leaden hue.

Where on Earth does it rain more often?

The frequency and intensity of rain in different parts of the planet depends on atmospheric pressure zones. In the region of the equator, the air is constantly heated, there is an area of ​​​​low pressure, and warm air, rising upward, is regularly cooled.


That is why huge rain clouds constantly form in the equator region and it rains heavily. This also happens in other areas of the planet, where the climate is determined by areas of low atmospheric pressure. The air temperature is also important: the higher it is, the more often it will rain in this place.

Where high pressure belts dominate, downward air currents reign. Cool air, sinking to the surface of the earth, heats up and becomes less saturated with moisture. At latitudes of 25-30 degrees it rarely rains, and at the poles there is almost no precipitation.

Humidity coefficient and precipitation observations

The level of humidity in a particular area is usually determined using the humidification coefficient. It is calculated by dividing the annual precipitation by the evaporation rate during the same time. The lower the humidification coefficient, the drier the climate.

Provided that the annual precipitation is approximately equal to evaporation, the humidification coefficient is close to unity. This picture is observed in forest-steppes and steppes. If the coefficient is greater than one, then the territory is characterized as an area with excess moisture. If the coefficient does not exceed 0.3, the territory is characterized as an area with poor moisture - such areas include deserts.


Climate scientists measure the amount of precipitation in a given part of the planet. Experts have recorded an absolute minimum of precipitation - this is the situation in the Libyan Desert and the Atacama Desert, where less than 50 millimeters of precipitation falls per year.

The absolute maximum occurs in the Pacific region (Hawaii) and Indian Cherrapunji, where more than 11 and a half thousand millimeters of rain falls every year.

Rain is one of the most common weather phenomena. However, not everyone knows why it rains, even though teachers gave this information in elementary school. The global water cycle begins with heat. Under the scorching rays of the sun, liquid evaporates from the surfaces of reservoirs, rivers, seas and oceans. It turns into steam and rushes upward. In countries with high humidity, small bubbles can be easily noticed.

Reasons for appearance

The sciences that study any type of precipitation are called meteorology and climatology. They identify 4 main reasons:

1. Elevated landforms.
2. Ascending movement of air masses.
3. The presence of water vapor, which contributes to the formation of precipitation in the form of rain.
4. Meeting and interaction of cold and warm air flows.

You can conduct a small experiment at home and see clearly how the global water cycle occurs.

To do this, you need to take a small container, fill it with water and put it on the fire to boil. The pan must be covered with a transparent lid. As the liquid heats up, it will begin to turn into steam, and small droplets will begin to accumulate on the surface of the lid, and then fall back into the pan of boiling water and turn into steam again.

Rising movements

The sun's rays heat the earth, and the process of moisture evaporation begins. This happens not only with soil, but also with water surfaces. The evaporated liquid is in the air. According to the laws of physics, warm air moves to the upper layers of the atmosphere along with the water bubbles it contains.

Basic physical concepts- absolute humidity (the amount of steam that is currently contained in the air) and relative humidity (in relation to the humidity that is observed at a given temperature). The hotter the air, the more water vapor it contains.

All air currents contain moisture, but the higher it rises, the lower the air temperature becomes. It begins to condense and clouds appear in the sky. When the temperature reaches its lowest point and the cloud is no longer able to hold the amount of moisture it contains, it begins to rain.

The process is similar to what happens with rising air masses. The rule of precipitation formation only works if the water bubbles have somewhere to come from - from a leaf plate, water surface, freshly plowed soil, etc.

But if a person is, for example, in the Sahara Desert, the sun's rays will not cause rain, since the moisture has nowhere to come from.

Every person has encountered this natural phenomenon. We have all hidden from the rain under umbrellas many times and have long been accustomed to checking before a walk whether there are any clouds in the sky. And the most curious are sure to ask the question, where does this rain come from?

Where does water for rain come from in the sky?

It turns out everything is very simple. Under the influence of the sun's heat, tiny droplets of water evaporate from the Earth's surface. These droplets are very small, almost invisible to the eye, such small droplets are called water vapor.

Water evaporates from the leaves of trees, from the surface of the earth, and even from the surface of our body. Most water, of course, evaporates in the form of steam from the water surface of rivers, lakes, seas and oceans.

Evaporation over water can be seen in the early morning when steam begins to form droplets directly above the water. You can also see such steam when the kettle is boiling.

Rising higher and higher, the steam enters the cold layers of the atmosphere and collects into water droplets and tiny pieces of ice. After all, the temperature at the top, where the clouds gather, is about zero degrees. The wind collects droplets into huge fancy clouds. You can see before the rain how white clouds gather into a cloud and darken before your eyes. This is because such a large amount of water collects in the sky that it does not allow sunlight to pass through.

It happens that droplets freeze due to low temperatures and, together with raindrops, fall to the ground. It's hailing.

The droplets in the cloud connect with each other, become heavier and begin to fall to the ground. So it starts to rain.

Why does it rain more often in autumn?

It rains in Russia in autumn even less often than in summer. According to weather forecasters, the greatest amount of precipitation falls in June. And in the fall, due to the large number of cloudy days, it seems to us that autumn is rainy.

In winter, evaporating water vapor does not even have time to form droplets, but immediately turns from steam into fluffy snowflakes. Yes, yes, snowflakes are formed from steam. And then instead of rain in winter it snows.

Now you know how water gets into the atmosphere and why it rains. Once on the soil in the form of rain or snow, the water goes into underground waters, into the seas, oceans, rivers, lakes, and other bodies of water, and everything starts again and again. This natural phenomenon is called the water cycle in nature.

Without such a water cycle, our planet would turn into a lifeless desert.

You can even create a small water cycle at home. To do this, cover with a transparent lid and put on fire. You will see how the steam will rise and settle on the lid in the form of droplets. And the drops will fall down, only to rise up again, turning into steam. Such wonderful rain in a pan.