What is the term used to denote the critical temperature at which the air becomes saturated with vapour and below which the condensation is likely to begin?

The term used to denote the critical temperature at which air becomes saturated with water vapour is the dew point. At this specific temperature, the relative humidity of a given sample of air reaches 100%, meaning the air is holding its full capacity of moisture [2]. If the air temperature is reduced to or below the dew point, the air can no longer hold the excess water vapour in a gaseous state, leading to the process of condensation [1]. This results in the formation of dew, frost, fog, or clouds depending on the environmental conditions [3]. While 'condensation point' is a descriptive phrase, 'dew point' is the precise meteorological term used to define the temperature at which saturation occurs at a constant barometric pressure [4].

Sources

1. [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 10: Water in the Atmosphere > CHAPTER > p. 86
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Dew point > p. 327
3. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 10: Water in the Atmosphere > EVAPORATION AND CONDENSATION > p. 87
4. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > 24.3. Condensation > p. 330