| S. No. | Relative humidity | Absolute humidity |
|---|---|---|
| 1. | It is the ratio between the actual amount of water vapour present in the air and the maximum amount of water vapour, the air can hold at that temperature. | It is the actual amount of water vapour present in the air regardless of temperature. |
| 2. | It is always expressed as a percentage. | It is expressed as grams of moisture per cubic metre of air. |
| 3. | Relative humidity of the air decreases with increase in temperature and vice versa. | Absolute humidity is independent of temperature and change in temperature has no effect on absolute humidity. |
| 4. | Relative humidity is more reliable and it is a measure of atmospheric humidity. | It does not tell us the amount of water which the air needs to become saturated. |
| 5. | Relative humidity is more in the mornings and at night and less in the afternoon as the temperature goes up. | Absolute humidity decreases from equator towards poles. Hot air can hold more water vapour than the cold air. |