Aviation meteorology

Study aviation meteorology through pressure, moisture, stability and weather systems, with examples that separate observations, forecasts and assumptions.

Aviation meteorology helps you connect the state of the atmosphere with the weather an aircraft may encounter. Start with the physical cause: what is heating, cooling, moving or changing state? Give the process a name before learning its report code.

This guide is organised for Airline Transport Pilot Licence aeroplane, or ATPL(A), study. The topic map groups European Union Aviation Safety Agency (EASA) Subject 050 from AMC1 FCL.310; FCL.515(b); FCL.615(b); FCL.835(d), October 2026 consolidation. It is an independent study guide, not exhaustive syllabus coverage or official endorsement.

A topic map for aviation meteorology

The separate EASA Private Pilot Licence aeroplane (PPL(A)) syllabus, AMC1 FCL.210; FCL.215, section 3, also includes atmosphere, moisture, stability, wind and weather information. These are PPL-relevant foundations, not evidence of identical examination depth. UK learners should use their training organisation’s current UK Civil Aviation Authority (CAA) requirements; EU syllabus references do not establish UK examination rules.

A recommended study sequence

Begin with pressure, temperature, density and altitude references. Learn what each quantity measures before combining them in a formula. Treat ISA as a defined comparison atmosphere rather than a forecast.

Move to moisture and changes of state, then to rising and sinking air. Once you can compare a parcel with its environment, connect stability to cloud development and lifting mechanisms.

Next, study wind, air masses, fronts and larger systems. Add hazards alongside the processes that produce them. Finally, practise interpreting weather products with their times, area, level and limitations visible. Revisit the physics whenever a code describes something you cannot explain. This is our editorial recommendation, not an official course order.

Four ways to reason through a question

1. Name the quantity and its reference

A pressure value is not a height until a pressure-to-height model and datum are specified. Likewise, an observed temperature and an ISA temperature are different inputs.

In an invented question, observed temperature at a stated pressure altitude is +5°C, while ISA temperature there is supplied as −5°C. The deviation is +10°C: 5 − (−5). It is warmer than ISA. That subtraction alone gives neither density altitude nor terrain clearance. Keep the quantity you have calculated attached to its name.

2. Compare temperatures at the same level

Take an unsaturated parcel initially at 18°C. Lift it 1,000 ft, using an explicitly assumed dry adiabatic cooling rate of 3°C per 1,000 ft. Its final temperature is 15°C. If the environment at that level is 16°C, the parcel is cooler and, in this simplified comparison, denser. Buoyancy opposes the upward displacement.

Assume pressure equilibrium, negligible mixing and heat exchange, no condensation, and negligible moisture effects on the density comparison. This illustrates a restoring tendency for this displacement, not the stability of an entire sounding. A saturated parcel follows a different temperature path. The distinction is explained in the UK MOD’s AP3456 Volume 10, Stability, chapter 10-2 (figures labelled 10CD-2).

3. Read the time before decoding the weather

A Meteorological Aerodrome Report (METAR) records an aerodrome observation. A Terminal Aerodrome Forecast (TAF) describes expected conditions over a validity period. Times use Coordinated Universal Time (UTC). Use these invented teaching extracts, with station identifiers and other groups omitted:

The observation reports wind from 240° true at 12 kt, 8,000 m prevailing visibility and broken cloud at 2,000 ft above aerodrome level. The forecast gives 10 kt, at least 10 km visibility and scattered cloud at 2,500 ft. These are not contradictory measurements: one reports conditions at an observation time; the other forecasts conditions during a period.

The Met Office’s METAR and TAF guides explain these groups. An extract cannot establish flight suitability. Real interpretation needs the complete current product, including amendments and change groups, plus other applicable information.

4. Keep temperature–dew-point spread in proportion

At 12°C with a dew point of 10°C, the spread is 2°C. Dew point is the temperature at which that air sample would become saturated when cooled at constant pressure without changing its water-vapour content. The spread describes closeness to saturation; it cannot guarantee cloud base or visibility. A surface pair does not describe moisture and temperature throughout the air above it.

Fog formation also depends on cooling, moisture, wind and mixing, as the Met Office’s explanation of fog illustrates. Do not turn a small spread into a promise that fog will form, or a larger spread into assurance that visibility is good.

Check your understanding

Is a TAF issued at 09:00 an observation at 09:00? No. Issue time identifies when a forecast was produced; validity identifies the period it describes.

Does rising air always remain warmer than its surroundings? No. Compare parcel and environmental temperatures at the same height, using the appropriate parcel process.

Does +10°C ISA deviation mean the air temperature is +10°C? No. It means the actual temperature is 10°C above the ISA value at the specified level.