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So why is it raining? Why does it rain and where does it come from? Why is it raining heavily

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 are faced with 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 continuous 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.

Rain is the most common type of precipitation. Even in elementary school, students are told where rain comes from. But despite the availability of teacher explanations, many unclear “whys” remain. For example, why is a small cloud capable of pouring down torrents of rain, while black clouds pass by without even splashing? Why do drops come in different sizes and how are they formed?

Rain and the water cycle in nature

It all starts with warmth. Solar energy causes water to evaporate from the surfaces of oceans, lakes, seas, rivers, other bodies of water, soil and even plants. Turning into steam, it rises into the air. The force of the wind speeds up the process. Small water particles are not tangible. At high humidity (especially in the tropical zone), you can notice how the bubbles circle around, not descending, but, on the contrary, tending upward.

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Causes of rain (formation of precipitation)

Climatology and meteorology - sciences directly interested in any precipitation, identify 4 main reasons for the appearance of rain:

  1. Rising air movements
  2. The presence of water vapor in the air in quantities sufficient to form rain
  3. Meeting of warm and cold air currents
  4. Presence of elevated landforms

Rising air movements

The sun heats the earth's surface, and moisture begins to evaporate from it. The process of evaporation occurs not only directly from the soil, but also from the surface of the ocean, sea, lake, as well as from leaf blades and human skin. All the water that has evaporated is still in the air. But, in accordance with the laws of physics, the heated air begins to slowly rise upward. Along with all the water contained in it.

You need to remember important physical concepts - relative and absolute humidity. Absolute is the amount of water vapor that is already, at the moment, contained in the air. Relative humidity is the humidity that exists relative to what it could be at a given temperature. And the last physical law is that the higher the air temperature, the more water vapor it can hold.

There is already some moisture in the rising air currents. But as you move upward, the air temperature drops. Therefore, moisture begins to condense into clouds. When the temperature drops even lower and the cloud can no longer hold the amount of moisture it contains, the excess falls out as rain.

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The presence of water vapor in the air in quantities sufficient to form rain

The process is similar to the one described above, only with clarifications. The rule of rain formation works if water vapor has somewhere to come from - from the surface of freshly plowed soil, a river, a lake, or a leaf plate of green cabbage and spinach seedlings. And if we are in the center of the Sahara Desert, then there will be no moisture in the air, no matter how much the sun shines.

Answer from Oksana[guru]
The sun warms the water in the ocean, in the sea, in the river, in any puddle.
The water evaporates, turns into transparent steam and rises upward, to where warm air currents carry it along with them, because warm air is lighter than cold air, it always tends to rush upward.
Light water vapor rises higher and higher from the earth heated by the sun and climbs high, to where it is constantly, even on the hottest summer day, very cold, like in winter.
The steam is warm, and when it touches cold air, it turns into tiny droplets of water.
The droplets are light, like fluff, they stay in the air perfectly, soar and move all the time, because everyone is pushing them; new and new streams of warm air rising from the ground.
Warm air throws droplets even higher, cold air drags them down; So they fly, tiny travelers, now up, now down; they dance, merge together, become larger.
There are very, very many of them, and all together they form a cloud.
At the top of the cloud the droplets freeze - it is very cold there; they turn into pieces of ice, grow, become heavier, and now they can no longer stay in the cloud and fall down. And when they fall, they melt, because it’s much warmer below; They become droplets of water again, merge together - and it rains on the ground.
It rains because there is water
Constantly strives for the ground.
Because it's already cold
And in heaven someone can't sleep.
Because when I fell in love with you,
I got lost among three pines,
Because, not loving warmth,
Sad autumn has arrived.
The author of the poems, unfortunately I don’t know who...

Reply from Elena Maksimova[newbie]
When heavy black clouds gather in the sky, people say: “It will rain.” More often than not, it actually starts. But where did the clouds come from, and why does it rain from them? The reason for all this is the Sun. It heats the surface of the planet and the water in the oceans, lakes and rivers turns into steam. It mixes with air.
Rising warm air spreads water vapor into the atmosphere. Cooling down, the air gives up part of its load, and invisible water vapor becomes water again. Clouds form from its droplets. This process, the opposite of evaporation, is called condensation. Inside the cloud, tiny droplets gradually grow, collecting more and more moisture. Finally, the drops become so large that they can no longer be held aloft by air currents and fall to the ground as rain.
Evaporation occurs throughout the day. Water vapor rises into the atmosphere. But in order for it to turn into clouds consisting of tiny droplets, solid particles are also needed on the surface of which the steam could condense. If there are no or very few dust particles or ice crystals in the air, condensation may not occur.
This is how events develop on a warm summer day, when in the morning the sun shines in the bright sky, and in the afternoon the clouds thicken and rain pours on the ground, sometimes a strong but short shower. These are local rains. Long, lingering rains, for two to three days, or even a week, are brought from afar by powerful air vortices - cyclopes. The inhabitants of the European plain are showered with rain from water that has evaporated from the surface of the Atlantic Ocean. By determining the speed of movement of the cyclone, meteorologists can predict the time of onset of rainy weather.
Have you ever wondered why it rains? Who is crying there in heaven? Maybe someone is feeling bad there at this moment? It's so bad that I can't hold back my tears. And they drip to the ground, falling from the cheeks of an angel sitting on a gloomy gray cloud... Do you know why there are different types of rain? In summer, angels are happy, and their tears appear only from happiness. That's why it rains when the sun shines. And it is reflected in their eyes. And from these highlights we get a rainbow.
And by autumn, the angels begin to feel sad, they cry more and more often and hide their eyes in the clouds... Then the tears fall to the ground sadly, quietly... This is the autumn rain. In winter, angels begin to feel sad without love... And tears, falling from their eyes down to the ground, turn into snowflakes, cold, prickly... Here they are... different rains...
Source: link


Reply from Vitaly Norokh[newbie]
water evaporates, water drips. simple


Reply from User deleted[active]
and in the high layers of the atmosphere, steam condenses into water and falls to the ground - it’s simple


Reply from Anna[guru]
Rain is the result of a complex and long-term process involving the sun, earth and air. First the earth is warmed by the sun. As a result, the water of the oceans, seas, lakes, as well as the moisture contained in the soil, turns into water vapor. This steam is then mixed with air. This is how the evaporation process takes place.
And then, together with the lighter warm air, water vapor rises high into the sky, where it cools and turns into clouds. This process is called condensation.
What happens next to the water vapor inside the clouds? The tiny droplets of water contained in the clouds gradually grow, absorbing more and more moisture. Finally the drops become so heavy that the air currents are unable to hold them, and they fall to the ground as rain. That's why it rains.
The process of water evaporation occurs almost around the clock, and water vapor rises. But it doesn't rain every day. It is not always the case that invisible vapors turn into visible raindrops. This is explained by the fact that a certain surface is required for the condensation process to occur. If there are few or virtually no dust particles in the air, then condensation does not occur. Snowflakes and ice crystals that are high in the clouds facilitate the condensation process.
If warm and cold air currents collide in the atmosphere, it will most likely result in rain. Warm air contains a lot of moisture, which is cooled by cold air currents. Invisible vapors turn into heavy drops of water, which fall to the ground.

After the director of one of the American radio stations got wet to the skin, caught in the autumn rain, a “Weather Forecast” program appeared on the air, which had not previously existed. The information turned out to be relevant, because it will never hurt to find out whether it is worth taking an umbrella today and whether you need to leave the house, since, for example, in Portugal, rain and wind are a valid reason for not showing up at work.

Rain is a type of precipitation that falls mainly from nimbostratus and altostratus clouds in the form of water droplets with a diameter of 0.5 to 7 mm. Rain usually comes from mixed clouds containing supercooled droplets or ice crystals.

Raindrops fall after small spherical particles of water merge into larger ones, or when they freeze to an ice crystal. Unlike the generally accepted opinion, they do not have the shape of a teardrop, since they are flattened on the bottom side due to the pressure of the oncoming air flow.

At first, these droplets are light enough that the air allows them to remain in the cloud. Since inside the cloud they are constantly moving and colliding with each other, merging and increasing in size, they begin to gradually descend downwards, continuing to increase. This process continues until the water particles gain the required mass, allowing them to overcome air resistance and shed raindrops on the ground.

If water particles are in clouds, where the temperature inside is high enough not to turn into ice crystals, the fusion of droplets with each other occurs constantly and extremely intensely. Rain does not come from them as often as from clouds, the temperature inside of which is below zero: in order to fall out of the cloud, ice crystals gain the necessary mass quite quickly.

If there is a very high difference in temperature between the cloud and the surface of the earth at this time, then the frozen crystals melt before reaching the earth's surface - and raindrops fall on the ground (the largest drops are produced when hail melts).

Interestingly, the larger the precipitation drops, the heavier the rain, but it usually passes quite quickly. The speed of such precipitation can range from 9 to 30 m/s (usually this is typical for summer or spring rain). But if the raindrops turn out to be small, then such precipitation can last for several days and even weeks - the water flies to the ground “slowly”, at a speed of 2 to 6.6 m/s, which is typical for autumn rains.

Precipitation intensity

One of the important indicators of precipitation in nature is the recording of rain intensity - the volume of raindrops falling over a certain time.

The thickness of the rainwater layer is usually measured in millimeters: one millimeter of water layer is equal to one kilogram of raindrops falling on one square meter (precipitation intensity usually ranges from 1.25 mm/h to 100 mm/h). Considering the amount of precipitation that falls over a certain period of time, light, moderate and heavy rain are distinguished.

Cover precipitation

At a speed of 2.5 mm/h, light rain falls regardless of the time of year at above-zero temperatures in moderate and high latitudes from dark altostratus, nimbostratus and cumulonimbus clouds. Covering precipitation lasts from several hours to several weeks and covers a vast area. If precipitation of this type is prolonged, then it quite often harms nature: the humidity in the atmosphere increases greatly, and plants begin to rot due to oversaturation with moisture.

Drizzle

Moderate rain falls at a rate of 2.5 to 8 mm/h in the form of small droplets from stratus and stratocumulus clouds. These precipitations do not last long, from several hours to two days, their quantity is minimal, and therefore the rain does not have a negative impact on nature.


Rainfall

Rainfall is heavy rain with wind, which often falls in temperate latitudes, usually during the warm season. Such heavy rain is characterized by a high rate of precipitation (more than 8 mm/h) and a short duration, no more than a few hours. The exception is May rain, which can last up to three days, as well as rainfall that falls in tropical and equatorial latitudes. The rainy season here often lasts several months, and torrential rain falls almost non-stop with an intensity of 25-30 mm/min.

It should be noted that thunderstorms are often accompanied by heavy rain, so in such weather it is better to find shelter in order to avoid accidents. It is interesting that the occurrence of a thunderstorm is directly related to the Sun - in mid-latitudes such a natural phenomenon can be observed in the afternoon and very rarely before dawn.


In Europe, the heaviest rain fell in Germany in the twenties of the last century, when its indicators were 15.5 mm/min. As for the heaviest precipitation on a planetary scale, rain with an intensity of 38 mm/min was recorded in the lands of Guadeloupe.

Heavy rain is often accompanied by thunderstorms and gusty winds, which causes significant harm to both nature and humans. The consequences of such rain and wind are often landslides, floods, and soil erosion. Such weather conditions can cause human death and also cause an environmental disaster. When it comes to heavy torrential rain, it is not so much its duration that is important as its intensity: the more drops that fall, the more harmful the consequences will be.

Rainy season

There are areas on Earth where the greatest amount of precipitation falls. This phenomenon is known as the "rainy season" and can be observed in tropical and subtropical latitudes. The closer to the equator the rainy season, the more prolonged the precipitation, lasting from May to October. In tropical regions more distant from the equator, the rainy season consists of two periods and gives people a certain respite (the rain belt does not stand still and gradually moves following the zenith of the Sun from the northern to the southern tropics and back).

Tropical summer rain usually begins suddenly, and the raindrops, having formed one continuous stream, pour onto the ground in such a dense wall that at a distance of one meter little can be distinguished. As a result, precipitation of such intensity can not only completely flood cities and villages in a few hours, but also cause mudflows and floods.

It is interesting that for local residents the rainy season is a common occurrence; they have long been accustomed to such weather conditions and know how to act, for example, almost all houses in Thailand are built on stilts. That is why tourists are not recommended to visit equatorial and tropical countries during this period. Storms and hurricanes also occur quite often; in the Philippines alone, during one rainy season, about thirty hurricanes and storms fly over the country.

Precipitation in temperate latitudes

The further from the equator, the weaker the rainy season is, and in temperate latitudes it disappears altogether: precipitation here is evenly distributed throughout the year and its abundance depends not so much on the Sun as on the winds and mountain ranges. For example:

  • Spring rain is typical for the entire territory of Europe and during the first two months the rains constantly alternate with the Sun. Showers often begin in the last days of spring;
  • In Germany, warm rain can be observed throughout the summer. In Sweden, Denmark, the Netherlands, and in central and eastern Europe, August is considered one of the rainiest months;
  • Autumn cold rain is observed in Norway, France, Italy and the Balkans in October and November, when warm weather gradually gives way to frost;
  • Winter cold rain can be seen mainly in the south of Europe - in the Balkans, in the west and south of the Iberian Peninsula, but it is also common in the northern territories, for example, it often falls in Scotland and the Faroe Islands.

Rains and nature

The role of precipitation in the life of nature is difficult to overestimate, since it both gives life and takes it away. Rain and wind, forming squalls, thunderstorms, and hurricanes, can destroy houses, destroy crops, nullify all a person’s efforts and even deprive him of life or health. The consequences of heavy rainfall are often catastrophic.

Raindrops also give life: after rainfall, nature is renewed and comes to life. For example, all mushroom pickers look forward to mushroom rain. This is a drizzling warm rain that falls from clouds located low above the earth's surface during the period of mushroom growth. It is interesting that, unlike other precipitation, mushroom rain does not last long, raindrops wet the soil well, and all the mushrooms in the soil begin to grow extremely well.

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 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.