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DGCA CPL METEOROLOGY · ASKED IN REAL EXAMS

Humidity

20 questions on this topic, recalled by candidates after DGCA sittings between 2021 and 2026. Together they were asked 44 times; the most repeated come first. Pick a year to see only what was asked that year.

Asked in:
Q1Asked in 9 sittings:Oct 2021 · Attempt 2Jun 2023 · RegularOct 2023 · OLODEDec 2023 · RegularMar 2024 · Regular 01Apr 2024 · OLODE 03Jan 2025 · OLODE 01Feb 2025 · OLODE 02May 2026 · OLODE 04

The temperature to which air must be cooled at constant pressure to become saturated is called the

  1. A.Wet bulb temperature
  2. B.Dew point
  3. C.Lapse rate
Show answer

B. Dew point

Cool air without adding or removing water vapour and at the dew point it is saturated; cool it further and the vapour condenses - dew, fog or cloud.

Q2Asked in 5 sittings:May 2024 · OLODESep 2024 · Regular 03Apr 2025 · OLODE 03May 2026 · OLODE 04Aug 2026 · OLODE 06

Air temperature, wet bulb temperature and dew point are all equal when

  1. A.The air is dry
  2. B.The relative humidity is 100%
  3. C.The pressure decreases
Show answer

B. The relative humidity is 100%

In saturated air no more water can evaporate, so the wet bulb cannot cool below the air temperature, and the air is already at its dew point - all three read the same.

Q3Asked in 3 sittings:Jun 2025 · Regular 02Mar 2026 · Regular 01May 2026 · OLODE 04

The ratio (in %) of the amount of water vapour present in the air to the amount it can hold at the same temperature is called

  1. A.Absolute humidity
  2. B.Relative humidity
  3. C.Specific humidity
Show answer

B. Relative humidity

Relative humidity compares what the air holds with what it could hold at that temperature. 100% means saturated.

Q4Asked in 3 sittings:Oct 2024 · OLODE 07Jan 2025 · OLODE 01Dec 2025 · Regular 04also in an undated previous-attempt paper

Relative humidity is defined as

  1. A.The amount of water vapour present in the air
  2. B.The ratio of the actual vapour pressure to the saturation vapour pressure at the same temperature
  3. C.The maximum moisture the air can hold
Show answer

B. The ratio of the actual vapour pressure to the saturation vapour pressure at the same temperature

RH = actual vapour pressure / saturation vapour pressure at the same temperature, as a percentage. It is a ratio, not an amount - the amount is absolute humidity.

Q5Asked in 3 sittings:2022 · Regular 03Jun 2023 · RegularMar 2024 · Regular 01

The actual amount (mass) of water vapour contained in a given volume of air is termed

  1. A.Relative humidity
  2. B.Specific humidity
  3. C.Absolute humidity
Show answer

C. Absolute humidity

Absolute humidity is grams of water vapour per cubic metre of air. Specific humidity is per kilogram of moist air; the humidity mixing ratio is per kilogram of dry air.

Q6Asked in 3 sittings:Jun 2023 · RegularMar 2025 · Regular 01Aug 2026 · OLODE 06

An air parcel is lifted until it becomes saturated. The temperature it has then reached is called its

  1. A.Potential temperature
  2. B.Dew point
  3. C.Wet bulb temperature
Show answer

B. Dew point

Rising air cools until its temperature meets its dew point; there it is saturated and cloud forms. At the condensation level the parcel's temperature equals its dew point.

Q7Asked in 3 sittings:Mar 2024 · Regular 01May 2024 · OLODEOct 2024 · OLODE 07

The amount of water vapour that air can hold depends mainly on its

  1. A.Pressure
  2. B.Temperature
  3. C.Speed
Show answer

B. Temperature

Warm air can hold far more water vapour than cold air - roughly double for every 10 °C or so. That is why cooling moist air leads to saturation.

Q8Asked in 3 sittings:Dec 2023 · RegularApr 2025 · OLODE 03Jan 2026 · OLODE 01

If air is cooled while its water vapour content stays the same, its relative humidity

  1. A.Increases
  2. B.Decreases
  3. C.Remains the same
Show answer

A. Increases

The vapour present stays the same but the amount the air could hold falls as it cools, so the ratio - the RH - goes up, until it reaches 100% at the dew point.

Q9Asked in 3 sittings:Jun 2023 · RegularJun 2025 · Regular 02Mar 2026 · Regular 01

With the onset of a sea breeze there is a ______ in temperature and a ______ in relative humidity

  1. A.Fall / Rise
  2. B.Rise / Fall
  3. C.Fall / Fall
Show answer

A. Fall / Rise

The sea breeze brings in cooler, moist air from the sea: the temperature drops and the relative humidity climbs.

Q10Asked in 2 sittings:Dec 2023 · RegularJan 2025 · OLODE 01

The lowest temperature to which air can be cooled by evaporating water into it until it is saturated is the

  1. A.Wet bulb temperature
  2. B.Dew point
  3. C.Dry bulb temperature
Show answer

A. Wet bulb temperature

A wet cloth on the thermometer bulb lets water evaporate, which takes heat from the bulb. The reading it settles at is the wet-bulb temperature. It lies between the dew point and the air temperature.

Q11Asked in 2 sittings:Mar 2022 · RegularJun 2025 · Regular 02

The humidity mixing ratio, when unsaturated air is lifted adiabatically

  1. A.Decreases
  2. B.Remains constant
  3. C.Increases
Show answer

B. Remains constant

The mixing ratio is the mass of water vapour per mass of dry air. Lifting or cooling a parcel adds or removes neither, so the mixing ratio stays constant until condensation starts.

Q12Asked in:Sep 2025 · Regular 03

The difference between the air temperature and the dew point is greater in

  1. A.Moist air
  2. B.Dry air
  3. C.Saturated air
Show answer

B. Dry air

The dew-point spread shows how far the air is from saturation. Dry air must cool a long way to saturate, so its spread is large; in saturated air the spread is zero.

Q13Asked in:Oct 2025 · OLODE 07

At the same sub-zero temperature, the saturation vapour pressure over ice compared with over supercooled water is

  1. A.More
  2. B.Less
  3. C.The same
Show answer

B. Less

The saturation vapour pressure over ice is lower than over water. Air that is just saturated for the water droplets is supersaturated for ice crystals, so the crystals grow at the droplets' expense - the ice-crystal process that makes rain in cold clouds.

Q14Asked in:Apr 2024 · OLODE 03

The difference between TT and TdTd is 3°C. The atmosphere is

  1. A.Very Dry
  2. B.Moist
  3. C.Saturated
Show answer

B. Moist

A spread of only 3 °C between the temperature and the dew point means the air is close to saturation - moist. The smaller the spread, the closer you are to cloud, mist or fog.

Q15Asked in:Aug 2025 · OLODE 06

Relative humidity depends on

  1. A.Moisture content and temperature of the air
  2. B.Temperature of the air only
  3. C.Moisture content and pressure of the air
Show answer

A. Moisture content and temperature of the air

Relative humidity compares the water vapour actually present with the most the air could hold at its temperature. Add moisture and it rises; warm the air and it falls, because warm air can hold more.

Q16Asked, wording rebuilt from a partial recall, in:Sep 2023 · Regular 03

The relative humidity of a sample of air depends on

  1. A.Its temperature and how much water vapour it holds
  2. B.Its pressure alone
  3. C.Its density alone
Show answer

A. Its temperature and how much water vapour it holds

Relative humidity compares the water vapour actually present with the most the air could hold at that temperature. So it moves with BOTH: add moisture and it rises, and warm the air - which raises the amount it could hold - and it falls, even though nothing has been taken out.

Q17Asked in 0 sittingsalso in an undated previous-attempt paper

The humidity mixing ratio is the ratio of the

  1. A.Mass of water vapour to the mass of dry air
  2. B.Mass of water vapour to the volume of dry air
  3. C.Volume of water vapour to the volume of dry air
Show answer

A. Mass of water vapour to the mass of dry air

Mixing ratio compares two masses - the mass of water vapour against the mass of the dry air it is mixed with, usually in grams per kilogram. Because it is a ratio of masses it does not change when the parcel expands or is lifted, which is why it is a useful way of tracking moisture.

Q18Asked in 0 sittingsalso in an undated previous-attempt paper

At the same sub-zero temperature, the saturation vapour pressure over water compared with that over ice is

  1. A.Less
  2. B.Greater
  3. C.The same
Show answer

B. Greater

It takes less energy for a molecule to escape liquid water than to escape the ice lattice, so at the same sub-zero temperature the saturation vapour pressure over water is the higher of the two. That difference drives the Bergeron process: in a cloud holding both, the ice crystals grow at the expense of the supercooled droplets.

Q19Asked in 0 sittingsalso in an undated previous-attempt paper

When the air is saturated, the spread between the free air temperature and the dew point is

  1. A.Large
  2. B.Least
  3. C.Unchanged from its usual value
Show answer

B. Least

The spread is the gap between the air temperature and the dew point, and it measures how close the air is to saturation. At saturation the air has been cooled right down to its dew point, so the two are equal and the spread is zero - the least it can be.

Q20Topic came up inalso in an undated previous-attempt paper

The difference between the air temperature and the dew point at a station is 3 °C. The air is

  1. A.Very dry
  2. B.Close to saturation
  3. C.Exactly saturated
Show answer

B. Close to saturation

The spread between temperature and dew point measures how far the air is from saturation. A spread of only 3 °C means very little further cooling is needed before condensation starts, so the air is moist and close to saturation. A spread of zero would mean it is saturated already.

These are candidates' recollections, not official DGCA papers: wording can differ from the paper as set. Every answer was checked against the DGCA CARs, AIP India, ICAO documents or worked calculation (independent check completed 17 Oct 2026). Spotted a mistake? Tell us and we will check it against the source.