In order to understand why monitoring humidity is important, you need to understand what humidity is. Humidity is the amount of water vapor present in the air referred to as absolute humidity. Water vapor is the gaseous state of water and is invisible to the human eye. Relative humidity is how saturated a space or a gas is with water vapor. It is the most commonly used measure of humidity and is generally expressed as a percentage with the symbol “%rh.”
When people say the humidity bothers them more than the heat, they are referring to the fact that when there is a lot of water in the air, it feels thicker and hotter and less comfortable. Relative humidity is affected by the dew point temperature which is basically a measure of how much moisture is in the air. You have probably heard meteorologist talking about the dew point in weather forecasts.