Explain relative humidity and the percentage of humidity?

Hint: Humidity tells us about the precipitation. So, humidity is the amount of water vapours, i.e. the gaseous form of water present in the environment or air. It is actually invisible but can be felt based on the water or moisture content present in the air. The more the water concentration in the air, the more humid the air is and hence the more humidity in the environment.

Complete answer:
Relative humidity is the ratio between the partial pressure of the water vapours and the vapour pressure of water at that particular temperature and pressure.
Always keep in mind that in humidity pressure and temperature plays a major role.
In simple terms we can say that, Relative humidity is the amount of actual water vapours present in the air at that particular temperature and pressure.
It is a percentage of how much moisture air can hold.
\[\% {\text{ Relative humidity = }}\dfrac{{{\text{Partial pressure of water vapour}}}}{{{\text{Vapour pressure }}}} \times 100\]
Also, with the increase in temperature, the amount of water vapours the air can hold increases.
Thus, we can say that, the higher the relative humidity, higher the water vapour content and more humid the air is and vice-versa. So, with less relative humidity, air is lighter, more cool and fresh.

Note:
As we learnt above, relative humidity tells us about the precipitation. So, as there is saturation to everything, so when air saturation occurs i.e. air holds the maximum amount of water vapour it can hold, then it has \[100\% \] relative humidity or complete saturation. Now, this is the condition when precipitation occurs i.e. raining takes place.