Meteorology

Relative Humidity

Definition

The ratio of actual water vapor in the air to the maximum amount it could hold at that temperature. 100% relative humidity means the air is saturated, and fog or clouds will form.

Related Terms

Dewpoint

The temperature at which air becomes saturated and moisture begins to condense. ...

Fog

A cloud at ground level that reduces visibility below 1 kilometer. Types include...

Test your knowledge

Think you understand Relative Humidity? Challenge yourself with practice questions covering meteorology and all other ATPL subjects.

Start a Practice Quiz

Or browse all questions by subject