Relative humidity, a percentage, is the ratio between the water vapor present and the air's saturation point, a figure that changes with the temperature.
相对湿度，是空气中绝对湿度与饱和湿度的比值，它随着温度变化。
2
Relative humidity RH refers to the humidity saturationpercentage of the air in certain volume.
相对湿度RH是指一定容积内空气的湿度饱和百分比。
3
Percentage ration of the actual vapour pressure in the air to the saturation vapour pressure with respect to water at the same temperature and pressure.