What is the measure of the amount of water vapor present in the air?

The measure of the amount of water vapor present in the air is referred to as humidity. Humidity indicates how much moisture is in the atmosphere, and it can be expressed in various ways, including absolute humidity (the actual amount of water vapor) or relative humidity (the current amount of water vapor relative to the maximum amount the air can hold at a given temperature).

Understanding humidity is important in meteorology and climate science as it affects weather patterns, comfort levels, and even agricultural practices. The other terms—dew point, precipitation, and temperature—relate to moisture and weather but do not directly measure the presence of water vapor in the air. Dew point refers to the temperature at which air becomes saturated with moisture, precipitation is the water that falls to the ground (like rain or snow), and temperature measures the warmth or coldness of the air, none of which equate to the direct measurement of water vapor content.