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Humidity vs. Relative Humidity: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on January 28, 2024
Humidity is the amount of water vapor present in the air; relative humidity is the percentage of water vapor in the air relative to the maximum amount the air can hold at that temperature.

Key Differences

Humidity refers to the concentration of water vapor in the atmosphere. Relative humidity, on the other hand, measures how saturated the air is with water vapor, expressed as a percentage of the maximum possible at a given temperature.
The level of humidity is an absolute measure and can be quantified in grams of water per cubic meter of air. Relative humidity changes with temperature, as warmer air can hold more water vapor.
High humidity means more water vapor in the air, which can make the air feel heavier or muggier. Relative humidity near 100% indicates the air is holding as much water vapor as it can at that temperature, often leading to precipitation.
Humidity is critical in various industries, like agriculture and meteorology, for understanding moisture levels in the air. Relative humidity is important in daily weather forecasts, providing information on how the air will feel to humans.
Humidity levels are important in preserving certain goods and in HVAC systems. Relative humidity is used to assess comfort levels indoors and to gauge potential for dew, frost, or fog formation.

Comparison Chart


Amount of water vapor in the air
Percentage of water vapor relative to maximum possible


Absolute measure (grams/m³)
Percentage (%)

Variation with Temperature

Constant at a given amount
Varies with temperature


Indicates moisture levels in air
Indicates how saturated air is with moisture

Impact on Perception

High humidity feels heavy or muggy
High relative humidity feels more humid or damp

Humidity and Relative Humidity Definitions


Indicates the amount of moisture in the air.
High humidity can make drying clothes outdoors difficult.

Relative Humidity

Indicator of how saturated the air is with moisture.
Relative humidity is often higher just before it rains.


Concentration of water vapor in the air.
The humidity in the rainforest is exceptionally high.

Relative Humidity

Measured as a percentage of moisture saturation.
Relative humidity is crucial in weather forecasting.


Absolute moisture content of the atmosphere.
Humidity levels are crucial in weather predictions.

Relative Humidity

Changes with temperature and moisture content.
Air conditioning can reduce indoor relative humidity.


Measured in grams of water per cubic meter.
HVAC systems are designed to control indoor humidity.

Relative Humidity

Affects human comfort and perception of heat.
High relative humidity can make a hot day feel hotter.


Essential in understanding atmospheric moisture.
Humidity is a key factor in agricultural planning.

Relative Humidity

Percentage of water vapor present relative to the maximum possible.
Relative humidity affects how we perceive temperature.


Dampness, especially of the air.


Relative humidity.


Dampness, especially that of the air.


The amount of water vapour in the air.


Moisture; dampness; a moderate degree of wetness, which is perceptible to the eye or touch; - used especially of the atmosphere, or of anything which has absorbed moisture from the atmosphere, as clothing.


The content of water vapor in the air, expressed as a percent of the maximum amount of water vapor that the air can hold at the given temperature; also called relative humidity. The capacity of the air to hold moisture increases with temperature, so if the temperature changes without changing the absolute content of the atmospheric moisture, the relative humidity will also change.


Wetness in the atmosphere


What is relative humidity?

Relative humidity is the percentage of water vapor in the air compared to what it can hold at that temperature.

Why does relative humidity change with temperature?

Because warmer air can hold more water vapor, relative humidity changes as temperature varies.

How is humidity measured?

Humidity is measured in absolute terms, like grams of water per cubic meter of air.

What is humidity?

Humidity is the amount of water vapor present in the air.

Can humidity be high when it's cold?

Yes, cold air can still contain a significant amount of moisture.

Does relative humidity affect asthma or allergies?

Yes, both high and low relative humidity can exacerbate asthma and allergies.

Is relative humidity important for weather forecasts?

Yes, it's crucial for understanding potential for dew, fog, or precipitation.

What affects indoor humidity levels?

Indoor humidity can be affected by activities like cooking, showering, and using humidifiers.

Does high humidity mean it will rain?

Not necessarily, but it can indicate a higher chance of precipitation.

How does relative humidity affect human comfort?

High relative humidity can make the air feel muggier and more uncomfortable.

What's a comfortable level of relative humidity indoors?

Typically, a relative humidity between 30% and 50% is considered comfortable indoors.

Why does humidity feel higher in the summer?

Higher temperatures allow air to hold more moisture, increasing humidity levels.

How do plants respond to humidity?

Plants can be sensitive to humidity levels, with some requiring more humid environments.

Can high humidity affect athletic performance?

Yes, it can lead to quicker dehydration and heat exhaustion.

Does relative humidity affect the spread of viruses?

Yes, some viruses are more stable in certain humidity conditions, affecting their spread.

How can humidity be controlled at home?

Using dehumidifiers, air conditioners, and proper ventilation can help control humidity.

Why is humidity important in agriculture?

It affects soil moisture, plant growth, and the risk of crop diseases.

Can low relative humidity be harmful?

Yes, it can lead to dry skin, irritated respiratory passages, and discomfort.

Can humidity damage electronics or furniture?

Yes, extreme humidity levels can cause damage to electronics and furniture.

Is relative humidity the same everywhere at a given temperature?

No, it can vary depending on local moisture sources and weather conditions.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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