Humidity: A Key Weather Variable — Passage and Quiz

Humidity is the amount of water vapor present in the air. It is a key weather variable that affects how comfortable we feel and plays a role in weather patterns like rain, fog, and dew.

Humidity is caused by the evaporation of water from oceans, lakes, rivers, and plants. When water evaporates, it turns into water vapor, which mixes with the air. The warmer the air, the more water vapor it can hold.

Humidity is measured using a hygrometer. There are different types of hygrometers, including mechanical ones that use human hair (which expands and contracts with humidity) and electronic ones that use sensors.

The most common unit for humidity is grams of water vapor per cubic meter of air (g/m³). However, humidity is often expressed as relative humidity, which is a percentage of the maximum amount of water vapor the air can hold at a given temperature.

High humidity can make the air feel hotter because sweat evaporates more slowly, reducing the body’s ability to cool down. Low humidity, on the other hand, can cause dry skin and respiratory issues.

Fun fact: The highest humidity levels are often found in tropical regions, where warm air holds large amounts of water vapor.