Rain is the result of water vapor condensing and precipitating, forming droplets that fall from clouds due to gravity.
There are always water vapor in the air. Warm air has more water vapor than cold air, which is why it is often humid in the summer.
The vapor becomes small water droplets or ice crystals. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.
Majority of us think raindrops look like teardrops; they truly look more like the top half of a hamburger bun, flattened on the bottom and with a curved dome top. Smaller drops are called cloud droplets, and their shape is spherical.
Not all raindrops are created equal. The size of falling raindrops depends on several factors, including where the cloud producing the drops is located on the globe and where the drops originate in the cloud.
Raindrops have sizes ranging from 0.1 to 9 millimeters (0.0039 to 0.3543 inch) mean diameter, above which they tend to break up.
At sea level and without wind, 0.5 mm (0.020 in) drizzle impacts at 2 m/s (6.6 ft/s) or 7.2 km/h (4.5 mph), while large 5 mm (0.20 in) drops impact at around 9 m/s (30 ft/s) or 32 km/h (20 mph).
The globally averaged annual precipitation over land is 715 mm (28.1 in), but over the whole Earth it is much higher at 990 mm (39 in).
By average annual rainfall, the wettest place is Mawsynram, Meghalaya, India, with 11,873 millimeters (467 inches) of rain per year. Meghalaya means ‘land of the clouds’. Most of the rain occurs during the monsoon season, between June and September.
The highest amount of rainfall ever recorded in one year is 22,987 mm (905.0 in) in Cherrapunji, India in 1861.
The highest amount of rainfall ever recorded in 24 hours is 182.5 centimeters (71.9 inches) in Foc-Foc, La Réunion. This occurred during tropical cyclone Denise on January 8, 1966.
Each second, approximately 16 million tons of water evaporates from the surface of the Earth. This 16 million tons of water is the same amount in raindrops that falls back to Earth each second. Water moves continuously in a balanced cycle based on its volume.
Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth.
It provides suitable conditions for many types of ecosystems, as well as water for hydroelectric power plants and crop irrigation.
Forests that experience high levels of rainfall are called rainforests.
Rain droplets contain dissolved nitrogen that comes from the air. This free and natural fertilizer makes grass look greener after rainfall.
Petrichor is the earthy scent produced when rain falls on dry soil. The word is constructed from Greek petra, meaning “stone”, and ichor, the fluid that flows in the veins of the gods in Greek mythology.
Rain can begin as snow, but by the time it reaches the Earth’s surface, it has melted because the temperature closer to Earth is warmer.
In certain conditions precipitation may fall from a cloud but then evaporates or sublimes before reaching the ground. This is termed virga and is more often seen in hot and dry climates.
Phenomenon of Yoro Fish Rain is just too weird and looks like a hoax – but it is not! The fish rain takes place in the beginning of rainy period somewhere in May – July. It is not known when this phenomenon started – first reports are from the middle of 19th century, when first missionary Father Subirana came here.
Blood rain or red rain is a phenomenon in which blood is perceived to fall from the sky in the form of rain. Cases have been recorded since Homer’s Iliad, composed approximately 8th century BC, and are widespread. Before the 17th century it was generally believed that the rain was actually blood. There is now a scientific consensus that the blood rain phenomenon is caused by aerial spores of green microalgae Trentepohlia annulata. Yellow, green, and black rain was also reported.
Rain with high levels of acid (a low pH) is called acid rain. Caused by the release of sulphur dioxide and nitrogen oxides into the air (often from factories and power stations), it can be harmful to plants and animals.
Rain is also known or suspected on other planets, where it may be composed of methane, neon, sulfuric acid, or even iron rather than water.
Rain was the cause of the weather forecasts on the radio. When the American owner of the station was caught in the rain, he established a new category of the weather forecasting, which talked about the rain several times a day.
Today it is possible to make up the artificial rain. Particles of dry ice thrown from the plane directly to the cumulus cloud. In a cloud, carbon dioxide is enveloped with water, and falls as a snowflake, heating on the road and turning into rain. Thus, we can combat with drought or to disperse the clouds.