Reporting Weather Conditions: Terminology and Procedures

Meteorological Language, ATIS, METAR, and TAF Explained With Practical Exercises

Weather is the single most significant variable in aviation. While modern aircraft are robust, understanding the atmosphere is critical for safety, efficiency, and comfort. Aviation uses a standard suite of coded reports and forecasts to relay information efficiently. This article provides a comprehensive guide to the structured language and standardized reports pilots use to decode and communicate meteorological conditions.

1 Why Standardized Weather Reporting Matters

Weather is one of the most dynamic and operationally significant factors in aviation. Accurate reporting and interpretation of meteorological information directly influence:

Route planning
Fuel calculations
Alternate selection
Approach type
Takeoff performance
Diversion decisions

Hence, aviation weather has its own vocabulary, designed for brevity and precision. This article provides a structured overview of:

Core meteorological terminology
ATIS procedures
METAR decoding
TAF forecasting
Practical interpretation exercises
Common reporting errors

Weather information in aviation must be:

Concise
Globally standardized
Time-sensitive
Unambiguous

Standardization is governed by the International Civil Aviation Organization (ICAO) and implemented globally to ensure consistency between pilots, controllers, and meteorological services.

Misinterpreting weather can lead to:

Unstable approaches
Runway excursions
Controlled flight into terrain (CFIT)
Fuel emergencies

2 Key Meteorological Terminology

Understanding terminology is the foundation of safe reporting.

A. Wind

Reported as:

Wind Velocity: reported as the direction (in degrees, true or magnetic depending on report) and speed (in knots, KT).

Example:
27015KT
Wind from 270 degrees at 15 knots.

With gusts:
270/15G25KT
Gusts up to 25 knots.

Wind Shear: A sudden, drastic change in wind speed and/or direction over a very small area, common during temperature inversions, critical during takeoff and landing. Encoded as WS{height}/{direction}{speed}KT.
Example: WS020/22035KT “WS” is wind shear “020” is 2,000 feet AGL (height in hundreds of feet), and “22035KT” is the forecasted wind direction and speed at that altitude.

Example:
ATC: SPLOT 123 Caution medium wind shear reported at 700 feet 3 miles final runway 12
PILOT: Roger SPLOT 123

B. Visibility

Visibility: the greatest distance at which prominent unlighted objects can be seen and identified by day. Measured and reported in:

Meters (most of the world)
Statute miles (SM in the USA)

Example:
9999 = Visibility 10 km or more
3000 = 3 km visibility

Low visibility is operationally critical for approach minima.

C. Cloud Coverage and Ceiling

Ceiling: The height above the earth’s surface of the lowest layer of clouds that is reported as Broken (BKN) or Overcast (OVC). A “few” or “scattered” layer does not constitute a ceiling.

Reported in oktas:

Code	Meaning
FEW	1-2 oktas
SCT	3-4 oktas
BKN	5-7 oktas
OVC	8 oktas

OVC: Overcast (8/8 sky covered)
BKN: Broken (5/8 to 7/8 sky covered)
SCT: Scattered (3/8 to 4/8 sky covered)
FEW: Few (1/8 to 2/8 sky covered)

Example:
BKN020
Broken cloud at 2,000 feet AGL. The lowest BKN or OVC layer.

Important for:

Instrument approaches
Alternate requirements

E. QNH

Altimeter Setting (QNH): The barometric pressure setting used to calibrate the altimeter for landing so it indicates the aircraft’s altitude above mean sea level (MSL) denoted by “A” followed by 4 digits (e.g., A2992) or “Q” and 4 digits (e.g., Q1013).
Example: A2992 (29.92 inches of mercury used in the USA) or Q1013 (1013 hectopascals used internationally).
Incorrect altimeter setting can cause altitude deviation.

3 ATIS = Automatic Terminal Information Service

The ATIS is a continuous broadcast of recorded aeronautical information in high-activity terminal areas (airports).

Purpose: To improve controller effectiveness and reduce frequency congestion by automating the repetitive transmission of essential routine information.
Key Feature: Each message is identified by a phonetic letter (e.g., “Information Bravo,” “Information Charlie”).
Pilots must listen to the ATIS before contacting ATC and state which information they have received.

ATIS provides continuous broadcast of:

Runway in use
Wind
Visibility
Cloud
Temperature & dew point
QNH
NOTAM information

Typical ATIS Structure

Example 1:
“Information Bravo. Time 1250 Zulu. Runway 27 in use. Wind 260 degrees 12 knots. Visibility 10 kilometers. Few clouds at 2,000 feet. Temperature 18. QNH 1015.”

Pilot readback:
“Information Bravo received.”

Example 2:
“Kraków Tower, SP-ABC, type Cessna 172, with Information Delta, request taxi.”

ATIS Safety Considerations

Always confirm current letter (Alpha, Bravo, Charlie…)
Avoid outdated information
Cross-check with updated METAR if needed

4 METAR

Aviation Routine Weather Report

METAR is an actual observation of the current weather at a specific airport. The report is issued typically every hour.
Purpose: To tell the pilot exactly what the weather is right now before landing or taking off.

METAR example 1:
ΕΡΚΚ 121850Z 24010KT 9999 BKN030 15/10 Q1013

Decoded:

EPKK: Kraków Airport
121850Z: 12th day of the month, 18:50 Zulu time.
24010KT: Wind 240 degrees at 10 knots.
9999: Visibility 10 kilometers or more.
BKN030: Clouds Broken at 3,000 feet.
15/10: Temperature 15°C / Dew point 10°C.
Q1013: Altimeter 1013 Hectopascals.

Example 2:
EPWA 121200Z 27015G25KT 3000 RA BKN020 OVC040 12/08 Q1013

Let’s decode:

Element	Meaning
EPWA	Airport (Warsaw)
121200Z	12th day at 1200 UTC
27015G25KT	Wind 270° 15 knots, gusting 25
3000	Visibility 3 km
RA	Rain
BKN020	Broken clouds at 2,000 ft
OVC040	Overcast at 4,000 ft
12/08	Temp 12°C / Dewpoint 8°C
Q1013	Pressure

Operational Interpretation

Gusty crosswind
Reduced visibility
Low cloud ceiling
Possible wet runway

Pilot actions:

Calculate crosswind limits
Review alternate
Consider performance penalties

5 TAF Terminal Aerodrome Forecast

TAF (Terminal Aerodrome Forecast)
The TAF is a concise statement of expected meteorological conditions at an airport during a specified period, usually valid for 24-30 hours.
Purpose: For flight planning, determining fuel requirements, and assessing if an alternate airport is necessary.

Example TAF

TAF EPWA 121100Z 1212/1318 26010KT 9999 SCT030 TEMPO 1215/1218 4000 TSRA BKN015

Decoded:

Valid from 12th 1200 to 13th 1800 UTC
Wind 260/10
Good visibility
Scattered at 3,000 ft

Temporary:

1500-1800 UTC
4 km visibility
Thunderstorms
Broken 1,500 ft

Important Forecast Terms

Code	Meaning
TEMPO	Temporary fluctuations
BECMG	Becoming
PROB30	30% probability
FM	From (rapid change)

6 Practical Exercises

Exercise 1: METAR Interpretation

Decode:
18005KT 1500 FG OVC002 05/04 Q1008

Questions:

What is the visibility?
What is the ceiling?
Is an ILS approach likely required?

Exercise 2: TAF Planning

Given:
PROB30 1400/1600 TSRA

Questions:

Would you consider an alternate?
What fuel impact might this have?
How would you brief the crew?

Exercise 3: ATIS Reporting Drill

Student must report:

Wind 320/18G30
Visibility 5 km
BKN012
QNH 1005

Correct spoken form:
“Wind three two zero degrees one eight knots gusting three zero…”

7 Common Errors in Weather Reporting

Error	Risk
Misreading wind direction	Wrong runway
Ignoring gusts	Landing instability
Misinterpreting TEMPO	Underestimating risk
Confusing QNH/QFE	Altitude deviation
Ignoring trend forecasts	Poor planning

8 Human Factors in Weather Communication

Under workload:

Numbers may be misheard
Rapid speech increases errors
Non-standard pronunciation creates confusion

Best practice:

Speak slowly
Repeat critical data
Confirm altimeter settings

9 Final Safety Principle

Weather reporting is not about reading codes it is about understanding operational consequences.
A METAR is data.
A professional interprets the risk behind the data.

10 Interpreting and Reporting

Activity 1: The Codebreaker

Decode the following METAR:
KLAX 151253Z 08004KT 10SM OVC015 10/05 A3001

[Decode your answer here]

KLAX: Los Angeles International
151253Z: 15th, 12:53 Zulu.
08004KT: Wind 080 at 4 knots.
10SM: Visibility 10 Statute Miles.
OVC015: Overcast ceiling at 1,500 feet.
10/05: Temp 10°C/ Dewpoint 5°C.
A3001: Altimeter 30.01 inches Hg.

Activity 2: The Pilot Report (PIREP) for General Aviation

You are flying SP-ABC at 6,000 feet and encounter moderate turbulence. You decide to submit a PIREP.
What is the correct standard response?

Correct PIREP Response:
“Kraków Center, Sierra Papa Alpha Bravo Charlie, PIREP. Encountering Moderate Turbulence at Six Thousand feet, type Cessna 182.”

Procedure Check: The Communication Loop

When you are contacting ATC for the first time, your report of the weather you possess is your “ticket to ride.”

Pilot Call: “Kraków Ground, SP-ABC, type Cessna 182, at GA apron, requesting VFR departure to the South, with Information Sierra.”
If you miss that last phrase, the controller cannot issue you taxi instructions. They must first verify that you have received the latest critical terminal data.

Safety Priority: The goal is that you have the data, not that you heard it on a recording.
Efficiency: If you don’t have the ATIS, you are making the controller’s job harder and increasing frequency congestion.

Standard Procedure: “Advise on initial contact you have information [Alpha/Bravo…]” is standard practice to ensure you have necessary, updated info.

The Lesson: In aviation, knowing the weather is mandatory. Knowing how to communicate it efficiently is the key to safe and orderly operations.