Q:

What causes rain?

A:

Quick Answer

Any time the droplets in clouds grow and come together to form drops that are large enough to create a speed of falling that is greater than the speed at which the cloud is blowing upward, then they head downward, and if they make it down without evaporating, people on the ground experience them as rain or snow. Sometimes rain evaporates again and heads back up into the clouds. The greater the amount of water vapor under the cloud and the stronger the winds on the updraft, the more likely precipitation becomes.

Know More
What causes rain?
Credit: Jose Luis Pelaez Inc Blend Images / 360 Getty Images

Full Answer

If there are clouds out and about but no rain, then the cloud lacks enough water vapor to form the precipitation or the cloud doesn't have enough rising motion inside of it. When air masses are warmer, rain usually takes place inside localized clouds featuring harder updrafts. When air masses are cooler, rain or snow happens within low pressure zones hosting larger cloud systems, generally appearing at the edge of cold and warm air masses.

Because the Earth is a closed system, the precipitation that takes place each year equals the amount of evaporation. Rain or snow always begins as water vapor that evaporates upward from the planet's surface.

Learn more in Rain

Related Questions

  • Q:

    How does precipitation form?

    A:

    Precipitation forms when condensation inside clouds occurs at the level that the droplets become heavy enough to fall down to the Earth's surface. Rain, hail, freezing rain, snow and sleet are all types of precipitation that result from different conditions in the atmosphere.

    Full Answer >
    Filed Under:
  • Q:

    What makes it rain?

    A:

    Rain and other forms of precipitation occur when water accumulates in the clouds and falls to the ground. This occurs due to the water cycle, which continually recycles the water on Earth.

    Full Answer >
    Filed Under:
  • Q:

    Where does it rain the most?

    A:

    As of 2014, the rainiest place in the world is Mawsynram, Meghalaya State, India, with about 467 inches of rainfall every year. This small mountain community is soaked during monsoon season every year, with about 90 percent of their annual rainfall falling at that time.

    Full Answer >
    Filed Under:
  • Q:

    Why is rain water naturally acidic?

    A:

    Rain water absorbs carbon dioxide from the air it passes through on its way down. The carbon dioxide reacts with the water to form carbonic acid. This mechanism is one of the principal ways in which atmospheric carbon is scrubbed from the air and put back into circulation among living systems.

    Full Answer >
    Filed Under:

Explore