What's the Difference?

Do you ever wonder what the difference is between dew point temperature and relative humidity, and why meteorologists focus more on the dew point temperature rather than humidity? It's because the dew point temperature is a more accurate way of showing the amount of water vapor in the air, and the impact it has on our comfort level.

For example, if both the air temperature and dew point temperature are at 60 degrees, the relative humidity is equal to 100 percent. But when the temperature is 100 degrees and the dew point temperature is 70 degrees, the relative humidity is about 40 percent. The relative humidity in this case is lower because it represents how much the atmosphere is saturated at a certain temperature, whereas dew point temperature represents the temperature at which air becomes saturated. The warmer an air mass becomes, the more moisture it is able to hold. So even though the relative humidity is 100 percent when both the air and dew point temperature are at 60 degrees, it feels more comfortable than when the air temperature is at 100 degrees and the dew point temperature is at 70 degrees. Anytime the dew point is higher than 60 degrees, it begins to feel uncomfortable.