humidity
n. uncountablen. the amount of water vapor in the air. When it is high, the air feels heavy and sticky, making you feel hotter than it actually is.
n. the concentration of water vapour present in the air. Often used in a relative sense to describe the atmospheric moisture content in relation to temperature.
The high humidity makes the summer heat feel much worse.
Tropical rainforests are known for their intense humidity, which supports a vast variety of plant life.
As the temperature dropped during the evening, the relative humidity rose until the air reached its dew point and a thick fog began to settle over the valley.
From Middle English humidite, borrowed from Old French humidité, from Medieval Latin hūmiditās, from Latin ūmidus (“damp, moist, wet”). By surface analysis, humid + -ity.