The ratio of the water vapour pressure actually present to the water vapour pressure required for saturation at a given temperature, expressed in percent.

The ratio of the amount of water present in air to the amount present at saturation. Most caves have high humidity because climatic conditions tend to be constant with very little evaporative moisture loss. But caves can have low humidity.

Ratio of the amount of water vapor in the air to the maximum amount of water vapor the air can hold at a given temperature.

the amount of water vapor in the air compared to the amount of water vapor the air can actually hold at a given temperature and pressure. When the air has a relative humidity of 100 per cent, it is saturated.

the percentage of moisture in the air measured against the amount of moisture the air could hold at a given temperature (e.g., since cold air is capable of holding less moisture than warm air, if the temperature drops and the moisture volume remains constant, the relative humidity will increase; conversely, if the temperature rises and the moisture volume remains constant, the relative humidity will decrease)

This indicates, as a percentage, the amount of moisture that air of a given temperature is actually holding in vapor form as compared to what it could hold at that same temperature when fully saturated.

The ratio of the weight of water vapor in a sample of air to the weight of water vapor that same sample of air contains when saturated; usually stated as a percentage.

The ratio, expressed as a percentage, of the amount of water vapor actually present in air of a given temperature. as compared with the greatest possible amount of water vapor that could be present in air at that temperature. Calculation of relative humidity can be done from tables, special slide rules or calculators, graphs, or complex equations. See also Hygrometer and Psychrometer.

The amount of moisture in the air expressed as a percentage of the maximum amount that the air is capable of holding at a specific temperature.

The percentage of moisture in the air in relationship to the amount of moisture the air could hold at that given temperature. 100% relative humidity would be rain.

The ratio of the weight of water vapor in the atmosphere to the weight the air would hold if completely saturated at that temperature, expressed as a percentage.

The relative humidity of a gas (or air) vapor mixture is the ratio of the partial pressure of the vapor to the vapor saturation pressure at the dry bulb temperature of the mixture.

The ratio of actual pressure of existing water vapor to the maximum possible (saturation) pressure of water vapor in the atmosphere at the same temperature, expressed as a percentage.

The ratio of the mol fraction of water vapor present in the air, to the mol fraction of water vapor present in saturated air at the same temperature and barometric pressure; approximately, it equals the ratio of the partial pressure or density of the water vapor in the air, to the saturation pressure or density, respectively, of water vapor at the same temperature.

The ratio of the actual partial pressure of the water vapor in a space to the saturation pressure of pure water at the same temperature.

Approximately, the ratio of the partial pressure or density of the water vapor in the air to the saturation pressure or density, respectively, of water vapor at the same temperature. More simply, the amount of water vapor actually present in the air, expressed as a percentage, compared to the maximum amount of water vapor that the air could hold under the same conditions.

Ratio of moisture in the air to the highest level of moisture content possible in the air at the same pressure-temperature conditions.