The humidity of air measured in percentage is called :

Humidity in the atmosphere is expressed in several ways, but relative humidity is specifically defined as the percentage of moisture present in the air compared to its full capacity at a given temperature [3]. While absolute humidity measures the actual weight of water vapor per unit volume (grams per cubic meter) and specific humidity measures the weight of water vapor per unit weight of air (grams per kilogram), only relative humidity is expressed as a percentage [5]. Relative humidity indicates the degree of saturation; for instance, air at its full capacity is rated at 100%, while air with no water vapor is 0% [2]. This measurement is a critical climatic factor because it determines the rate of evaporation and changes significantly with air temperature fluctuations [3]. Therefore, when humidity is measured in percentage, it refers to relative humidity [1].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Relative Humidity > p. 326
2. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 10: Water in the Atmosphere > CHAPTER > p. 86
3. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Specific Humidity > p. 328
4. [5] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 13: Weather > Notes > p. 120
5. [2] Exploring Society:India and Beyond ,Social Science-Class VII . NCERT(Revised ed 2025) > Chapter 2: Understanding the Weather > LET'S REMEMBER > p. 38