Humidity (absolute or actual humidity) :

is the amount of moisture in air

measured in grams of water per kilogram of air (g/kg)
Saturated air:

is air containing the maximum amount of moisture possible

the saturated humidity depends on temperature (warmer air can “hold” more water vapour
Dew Point temperature:

the temperature that dew (condensation) will form when air is cooled

humid air has a high dew point, dry air has a low point
Relative Humidity:

a measure of humidity in comparison to the maximum possible

at 100% R.H., the air is completely saturated and the dew point is the SAME as the actual air
temperature (rainy, foggy days and nights when dew or frost forms)

in summer, high humidity makes the air feel “muggy or sticky” because water evaporates very
slowly from our warm skin and sweating doesn’t cool us down

in winter, high humidity feels cool and damp because the moist air absorbs heat from our skin
RH =
actual (dew point) humidity X 100%
Maximum (actual temperature) humidity