What is the Difference Between Humidity and Relative Humidity?

The main difference between humidity and relative humidity lies in how they measure the amount of water vapor in the air. Here are the key differences:

• Humidity: This term refers to the amount of water vapor present in the air. It can be expressed as absolute humidity, which is the measure of water vapor in the air regardless of temperature, and is expressed as grams of moisture per cubic meter of air (g/m³).
• Relative Humidity: This measures the amount of water vapor in the air relative to the temperature of the air. It is expressed as the amount of water vapor in the air as a percentage of the total amount that the air can hold at its current temperature. Warm air can hold more moisture than cold air, so relative humidity changes with air temperature.

In summary:

• Humidity measures the actual amount of water vapor in the air, while relative humidity measures the amount of water vapor in the air relative to the air's temperature.
• Absolute humidity is a measure of water vapor in the air regardless of temperature, while relative humidity is a measure of water vapor in the air as a percentage of the total amount that the air can hold at its current temperature.
• Relative humidity is commonly cited in weather forecasts, as it affects how we "feel" temperature.

Comparative Table: Humidity vs Relative Humidity

Here is a table comparing the differences between humidity and relative humidity:

In summary, humidity is the absolute amount of water vapor in the air, while relative humidity is the amount of water vapor in the air compared to the maximum amount possible at a given temperature and pressure. Relative humidity takes into account temperature and pressure, whereas humidity does not.