What is the Difference Between Absolute and Relative Humidity?

🆚 Go to Comparative Table 🆚

The main difference between absolute and relative humidity lies in their relationship with temperature. Absolute humidity is the measurement of water vapor within a given volume of air, regardless of temperature, and is expressed in grams of water vapor per cubic meter of air (g/m³). On the other hand, relative humidity is typically expressed as a percentage and refers to the amount of water vapor in the air relative to the maximum amount of water vapor that could be present in the air at a given temperature.

Key differences between absolute and relative humidity include:

  • Temperature Independence: Absolute humidity is independent of temperature, while relative humidity is a function of temperature.
  • Measurement: Absolute humidity is the mass of water vapor divided by the mass of dry air within a specific volume of air at a given temperature. Relative humidity, however, indicates the actual moisture content compared to the potential moisture content of the air.
  • Applications: Relative humidity is cited in weather forecasts as it affects how we "feel" temperature. Absolute humidity is more relevant in scientific and industrial applications.

In summary, absolute humidity is a measure of the total mass of water vapor in the air regardless of temperature, while relative humidity is a measure of the amount of water vapor in the air relative to the maximum amount that could be present at a given temperature.

Comparative Table: Absolute vs Relative Humidity

The main difference between absolute and relative humidity lies in their definitions and how they are affected by temperature. Here is a table summarizing the differences between the two:

Parameter Absolute Humidity Relative Humidity
Definition The actual amount of water vapor present in the air, expressed in grams of moisture per cubic meter of air (g/m3). The amount of water vapor in the air relative to the air's temperature, expressed as a percentage.
Temperature Dependence Independent of temperature. Dependent on temperature, decreasing as temperature increases and vice versa.
Expression Fraction (g/m³). Percentage (%).
Affected by Land and water distribution on Earth and seasonal changes. Geographic location and temperature.

In summary, absolute humidity measures the actual amount of water vapor present in the air regardless of temperature, while relative humidity measures the amount of water vapor in the air relative to the air's temperature. Absolute humidity is expressed as a fraction (g/m³), whereas relative humidity is expressed as a percentage (%).