Humidity (Meaning and Explanation)

We explain what humidity is, what types exist and how it is measured. Also, humidity in the climate and how clouds form.

What is humidity?

humidity is the amount of water vapor contained in the air. There is always water vapor in the air and the amount varies depending on various factors, for example, if it recently rained, if you are near the sea, whether or not there is vegetation on the ground, the air temperature, among others.

This means that Any place that has the presence of water with the possibility of heating and evaporating is a source of humidity such as that which comes from the surface of rivers, lakes, moist earth and plants, where water can be present in solid (frozen), liquid and gaseous (vapor) states.

Humidity in the climate

humidity climate atmosphere — The study of climate is based on the analysis of temperature, pressure and humidity.

Climate is the result of numerous factors that act together. Geographical features, such as mountains and seas, decisively influence its characteristics. That's why, To determine the climate it is essential to analyze the temperature, air pressure and humidity.

Hygrometry is the part of physics that studies the causes of humidity in the atmosphere and the measure of its variations. Its name derives from the Greek, hygroscopy, hygro which means “wet” and scopy which means “examination”.

Types of humidity

The types of humidity can be:

Relative humidity. It is the capacity of air to store water, which depends on the saturation point (limit of that air to contain water) and a certain temperature. Its calculation is defined by the quotient between the amount of vapor present in the atmosphere, divided by the maximum amount it could contain, multiplied by one hundred (and the result is expressed as a percentage). A relative humidity of 100% indicates that it has reached its saturation limit point and, from there, any excess water vapor condenses (becomes liquid).
Absolute humidity. It is the mass of water vapor that is present in a certain volume of air, before it is condensed (relative humidity). It is important to highlight that temperature conditions absolute humidity: hot air masses have a greater capacity to store water vapor than cold air masses. Absolute humidity is expressed in grams per cubic meter.

Humidity sensor

humidity hygrometer — The hygrometer measures the humidity present in the air or other gases.

Humidity can be measured with sensors. Among them, the following stand out:

The hygrometer. It allows determining the degree of humidity of the air or other gases. In meteorology, it measures the moisture content in the atmosphere.
The psychometer. It allows you to determine the amount of vapor that must be added to humid air to saturate it, that is, it indirectly measures humidity.

The clouds

Clouds are formed by water droplets and other particles suspended in the air. These drops come from the condensation of water vapor. If there are clouds in the sky, a moist air mass has cooled enough to become saturated and begin condensation.

If there are no clouds, it does not mean that there is no humidity: the air always contains some water vapor but, sometimes, it does not contain enough to condense.