What is humidity and how does humidity affect weather

Looking at a weather forecast today, we can easily find that humidity is one of the major pieces of information listed together with other ones like temperature, rainfall, wind speed, UV index, cloud cover, the chance of rain, etc. But have you ever asked yourself the question of “What is humidity and how does humidity affect weather?” If you have, check out this article to get the answer now.

What is humidity?

Humidity … It sounds so familiar to us and perhaps, all of us know that humidity is something related to the amount of water having in the air. But when it comes to a clear explanation of what humidity really is and how it affects the weather, we bet that it will make you a bit confused, right? Don’t worry about that as of right below here, we are going to learn basic things about humidity, from what it is, to how does humidity affect weather and more. Let’s do it right now!

What is humidity?

Humidity simply is the presence of water vapor in the atmosphere at a specific time and measured in percentage (%) or grams per cubic meter (g/m3). And about water vapor, it is the water in a state of gas (that’s formed after the water has evaporated).

The more water evaporates and the more water vapor in the atmosphere in a given area, the higher the percentage of humidity in that area will be. That means hot places tend to have higher levels of humidity in the air than cool places since heat makes water evaporate faster.

Of course, we don’t see it but we are always surrounded by air that contains a certain amount of humidity. The percentage of humidity or water vapor in the atmosphere determines how we feel when we are outside.

Humidity simply is the presence of water vapor in the atmosphere

It also affects the health of plants and animals around us. Humidity is an important factor determining the formation of clouds as well as directly affecting the weather. And we will deeply learn about “how does humidity affect weather?” in the third part of this article.

In fact, it’s always so important to have the right amount of water vapor or the right percentage of humidity in the atmosphere to maintain a “balanced” air ratio. Too much or too little humidity in the air can negatively impact our lives and the environment as well.

Absolute humidity and relative humidity

Absolute humidity and relative humidity are 2 primary measurements of humidity. Obviously, they are different measurements but in fact, there’s still some confusion about them. Right now, we are about to make clear basic differences between absolute and relative humidity.

How does humidity affect weather: Relative humidity vs absolute humidity

Absolute humidity

Absolute humidity is the ratio of water vapor to the dry air in a volume of air and it does not take temperature into consideration. Absolute humidity is normally expressed in grams per cubic meter (g/m3) or the number of grams of moisture per one cubic meter of air.

Relative humidity

Differing from absolute humidity, relative humidity takes the temperature into consideration to measure the level of humidity in the air. It’s expressed as a percentage that’s equal to the amount of water vapor present relative to the maximum water vapor that the air is capable of holding at its current temperature.

In fact, relative humidity is more common than absolute humidity when it comes to measuring the amount of moisture or water vapor in the atmosphere at a given time. That’s why we always see the percent of humidity level in the weather forecast today, weather forecast tomorrow, 10 days weather forecast, ...

When relative humidity reaches 100%, that means the air is saturated and the moisture in it will either condense as dew or fall out of the air as rain.

A digital hygrometer for home

Which instrument is used to measure humidity?

So, do you know the name of the instrument that is used to measure humidity? Well, that’s nothing but the hygrometer which is used to measure relative humidity.

Of course, there is a wide range of instruments that have been used to measure humidity throughout the years. And the psychrometer is definitely one of the most well-known early examples of humidity measuring instruments.

The psychrometer basically has 2 thermometers of dry-bulb and wet-bulb, and the difference in these two thermometer readings is used to determine the humidity in the atmosphere.

How does humidity affect weather?

Humidity is one of the major driving forces of almost all weather systems on the planet. Indeed, the combination of temperature and humidity is the impetus of a number of weather systems and occurrences.

Of course, humidity affects weather in a lot of different ways, and in this article, we are going to introduce some of the most basic aspects regarding how humidity affects weather.

Humidity and cloud formation

Cloud formation

How does humidity affect weather? The first thing we want to mention here is the cloud formation. We all know that when the sun shines and produces heat, the ground will absorb that heat and also radiate some of it back into the air, warming the air that’s close to the ground, right?

Warm air is always lighter than cool air, so it rises and then an upward convection current is formed. When ground air is full of water vapor or moisture, then the moisture also rises with the warm air.

The moist air in the warm front will cool down as it moves over the cold front in the upper atmosphere. And since cool air is capable of holding less moisture than warm air, the water vapor will condense into mist or ice particles when the temperature is cold enough. From the ground, well, this condensation is perceived as clouds. 

How does humidity affect weather: hurricanes develop in the extreme moisture conditions combined with high temperatures over tropical oceans

Thunderstorm and hurricanes

Once again, the combination of warm air and humidity is mentioned here. Let’s see how does humidity affect weather here!

Warm air is capable of holding a large amount of moisture, and both of them - the air and moisture - rise quickly. The moisture cools down rapidly when it is in the upper atmosphere, resulting in the forming of large clouds that will spread out in the reduced pressure conditions.

The rapid upward flow of air then creates the low-pressure areas near the ground, and of course, the cooler air will quickly rush in to fill these low-pressure areas. The outcomes of this circulation of moisture and air are strong wind, dark clouds, and rain of a thunderstorm.

About hurricanes, they develop during the summer months in the extreme moisture conditions combined with high temperatures over tropical oceans. They are strongly fueled by the rapid evaporation of ocean water. However, hurricanes typically lose their energy and become very destructive when they make landfall.

A beautiful misty scenery 

Coastal and mountainous climate zones

Clouds block the sunlight and keep the air underneath cool which helps increase the relative humidity in the atmosphere. When the air gets saturated, rain starts falling, but even before the precipitation, the air can be misty and foggy. At a given time, precipitation, as well as condensation, cool the air enough to stop the convection, and then the clouds break.

This cycle repeats itself frequently in the areas near large bodies of water like the beach, for example, but very rarely ever occurs in places like deserts where there is a lack of a source of evaporating waters.

However, clouds can still form in mountainous areas even in case the humidity is low. This is because updrafts on the slopes help push the air higher. And when the air gets cool near the peaks of the mounter, the moisture that it contains will all condense.

Conclusion

Do you agree with us that humidity and things related to this term are all quite complicated to understand? But after all, we hope that this article helped you know a little bit more about humidity and aspects related to humidity. At least, now we know what humidity is and it is one of the major driving forces of a lot of weather systems on the planet. Though humidity is normally invisible to our naked eyes, it directly affects the weather, environment, and our lives as well. That’s all for today’s article. Finally, we hope that you found this article of “What is humidity and how does humidity affect weather?” interesting and useful.

Sources:

sciencing.com/humidity-affect-weather-10033063.html

ownyourweather.com/what-is-humidity-and-how-does-it-affect-weather/

goblueox.com/blog/what-is-humidity-and-why-does-it-matter/