Understanding Relative Humidity Basics | Generated by AI
Relative humidity (RH) is a measure of the amount of water vapor (moisture) present in the air compared to the maximum amount the air could hold at a given temperature. It’s expressed as a percentage: for example, 50% RH means the air contains half the moisture it could theoretically hold before becoming saturated (which would lead to dew or condensation).
Key Points
- Temperature matters: Warmer air can hold more water vapor, so the same amount of moisture will result in a lower RH on a hot day than on a cold one. As temperature rises, RH typically drops unless more moisture is added.
- Why it feels “humid”: High RH (e.g., above 60-70%) makes the air feel muggy because sweat evaporates more slowly from your skin, slowing your body’s cooling process.
- Measurement: It’s calculated using the current vapor pressure divided by the saturation vapor pressure at that temperature, often reported in weather forecasts alongside temperature.
In everyday terms, low RH (like in dry deserts) can make skin and eyes feel parched, while high RH (like in tropical areas) promotes discomfort and mold growth.
References
Humidity - Wikipedia Discussion on Humidity - National Weather Service Relative Humidity – What Is It And Why Is It Important? - Vaisala