What is the Difference Between Dew Point and Humidity?

Dew point and humidity both measure the amount of water vapor in the atmosphere, but they differ in their nature and the way they are measured. Here are the main differences between the two:

1. Temperature-dependency: Relative humidity is temperature-dependent, while dew point is not. Relative humidity measures the amount of water vapor in the air relative to the maximum amount of water vapor the air can hold at a given temperature. Dew point, on the other hand, is the temperature at which the air must be cooled to achieve a relative humidity of 100%.
2. Measurement: Dew point provides a more accurate measure of the actual amount of water vapor in the air. Relative humidity can be misleading because it changes with temperature. For example, a temperature of 30 degrees Fahrenheit and a dew point of 30 degrees Fahrenheit will give a relative humidity of 100%, but a temperature of 80 degrees Fahrenheit and a dew point of 60 degrees Fahrenheit will produce a relative humidity of 50%. It would feel much more "humid" on the 80-degree day with 50% relative humidity than on the 30-degree day with 100% relative humidity due to the higher dew point.
3. Comfort levels: Dew point is a better measure of how humid it feels outside. Air with a lower dew point is drier than air with a higher dew point. In general, dew points in the 50s or lower are comfortable for most people, while dew points in the 60s or higher feel increasingly muggy.

In summary, dew point is a more reliable and accurate measure of the amount of moisture in the air and the perceived humidity, while relative humidity is a temperature-dependent measure that can be misleading.

Comparative Table: Dew Point vs Humidity

Dew point and humidity are both measures of moisture in the air, but they differ in their definitions and the way they are used to describe the conditions of the air. Here is a table outlining the differences between the two:

In summary, dew point is a more accurate measure of how muggy or humid the air feels, while humidity, specifically relative humidity, is a percentage that compares the amount of water vapor in the air to the maximum amount the air can hold at a specific temperature.