humidity
Humidity is the amount of water vapor in the air. Humidity varies from place to place. It also varies in the same place from season to season. On a summer day in Atlanta, Georgia, humidity is high. The air feels very heavy and sticky. On a winter day in Flagstaff, Arizona, humidity is low. The air sucks moisture out of your nose and lips. Humidity can change rapidly if a storm comes in. Humidity can vary over a short distance, like near a lake. Even when humidity is at its highest, water vapor makes up only about 4% of the atmosphere.