Too much heat or humidity makes us uncomfortable, but the way the humidity is reported can be misleading.
For example, 90% humidity does not mean the air is 90% water vapor, explains Meteorologist John Wheeler.
The actual percentage of water vapor in the air by volume varies around 2%.
The relative humidity is really the percentage of saturation, and how much the water vapor the air can hold.
Wheeler further illustrates this by highlighting water can be added to a sponge to a point but then the sponge can't hold any more water.
Well, warmer air can hold more water vapor than cooler air, it holds less.
This is why the relative humidity goes up, and dew is more likely at night when the air cools down.
Confused? Well, the dew point makes this way simpler.
Dew point is the point at which the water vapor is squeezed out of the air as dew.
The higher the dew point, the sticker the air will feel.
Here's a quick guide to the dew point, when that Dew Point is below 50, it will never feel humid.
But as the dew point rises through the 60s, we feel that moisture, more and more.
A dew point above 70, that's sultry.