Humidity: the measure of the amount of water vapor in the air, used in weather reports and indoor climate control.
今日は湿度が高くて蒸し暑い。
The humidity is high today, so it's muggy.
湿度計で室内の湿度を確認した。
I checked the indoor humidity with a hygrometer.
適切な湿度は快適な睡眠にも重要だ。
Proper humidity is important for comfortable sleep as well.