Humidity and Temperature

Humidity is the measure of water vapor in the air and the amount of water vapor air can hold depends on the temperature of the air.

Because air is a gas, its specific heat capacity is very low. This means that its temperature changes very easily. To account for this, humidity is always expressed as relative humidity.

Relative humidity is always shown as a percentage. As you can see from the graph on the right, the higher the temperature, the more water vapor the air can hold.

Source: Relative Humidity | WikiMedia