Introduction
A METAR is one of the most important weather reports used by pilots. It gives a coded summary of the observed weather at an aerodrome at a specific date and time.
For a new student pilot, a METAR may initially look like a random collection of numbers, letters, and symbols. However, the information usually appears in a standard order. Once this order is understood, decoding a METAR becomes much easier.
Indian student pilots use METAR information to assess wind, visibility, weather, clouds, temperature, dew point, atmospheric pressure, and short-term weather trends.
A METAR alone does not provide a complete flight briefing. However, it is an essential starting point for deciding whether present conditions are suitable for circuits, solo flights, navigation exercises, departures, and landings.
What Is a METAR?
METAR is a coded aviation weather report that describes the actual observed conditions at an aerodrome.
It commonly includes:
- Aerodrome identifier
- Observation date and time
- Surface wind
- Visibility
- Runway visual range
- Present weather
- Cloud amount and height
- Temperature
- Dew point
- QNH
- Recent weather
- Wind-shear information
- Short-term trend
METAR describes observed weather. It is different from a TAF, which describes forecast weather.
Why METAR Knowledge Is Important
Understanding METAR information helps a student pilot evaluate:
- Runway suitability
- Crosswind conditions
- Tailwind risk
- Visibility
- Fog or haze
- Thunderstorm activity
- Cloud base
- Possible carburettor icing conditions
- Altimeter setting
- Weather improvement or deterioration
A student pilot should not simply decode the report. The decoded information must be connected with aircraft limitations, flying-school procedures, personal limits, and the planned training exercise.
Standard METAR Reading Order
A useful reading sequence is:
Report type → Airport → Time → Wind → Visibility → RVR → Weather → Clouds → Temperature → Dew point → QNH → Additional information → Trend
Reading every METAR in this order helps students avoid missing important information.
Basic Training Example
Consider this fictional METAR:
METAR VIDP 160530Z 09006KT 3000 HZ SCT020 31/25 Q1002 NOSIG
This is a training example and not a current weather report.
The complete meaning is:
A routine weather report for Delhi, observed on the 16th at 05:30 UTC. Wind is from 090 degrees at 6 knots. Visibility is 3,000 metres in haze. Scattered clouds are present at 2,000 feet. Temperature is 31°C, dew point is 25°C, and QNH is 1002 hPa. No significant short-term change is expected.
Let us decode each group separately.
METAR
The word METAR identifies the message as a routine aerodrome weather report.
Other possible report identifiers include:
- SPECI – special weather report
- METAR AUTO – automated report
- COR – corrected report
- NIL – report unavailable
A SPECI may be issued when significant weather changes occur between routine reports.
VIDP
VIDP is the four-letter ICAO location indicator for Delhi’s Indira Gandhi International Airport.
Some common Indian ICAO airport codes include:
| ICAO code | Airport or city |
|---|---|
| VIDP | Delhi |
| VABB | Mumbai |
| VOBL | Bengaluru |
| VOMM | Chennai |
| VECC | Kolkata |
| VOHS | Hyderabad |
| VAAH | Ahmedabad |
| VIJP | Jaipur |
| VAPO | Pune |
| VOCI | Kochi |
| VOGO | Goa |
| VEGT | Guwahati |
Students should always confirm the airport identifier before interpreting the weather. Reading the correct report for the wrong aerodrome can lead to unsafe planning.
160530Z
This group gives the observation date and time.
- 16 means the 16th day of the month.
- 0530 means 05:30.
- Z means UTC, also called Zulu time.
India Standard Time is UTC plus 5 hours and 30 minutes.
Therefore:
05:30 UTC = 11:00 IST
Another example:
181800Z
This means the 18th day at 18:00 UTC.
In India, this becomes:
23:30 IST on the 18th
A late UTC time may convert to the following calendar day in India, so students must check the date carefully.
09006KT
This is the wind group.
- 090 means the wind is coming from 090 degrees.
- 06 means the wind speed is 6 knots.
- KT means knots.
The wind is therefore coming from the east at 6 knots.
Wind direction always indicates where the wind is coming from.
Gusting Wind
Example:
24012G22KT
This means:
- Wind from 240 degrees
- Average speed 12 knots
- Gusting to 22 knots
The gust value is important because it may affect:
- Crosswind limits
- Airspeed control
- Circuit stability
- Approach technique
- Landing distance
- Go-around decisions
A wind of 12 knots gusting to 22 knots should not be treated as a simple 12-knot wind.
Variable Wind
Example:
VRB03KT
This means the wind direction is variable at 3 knots.
Another example:
18010KT 140V220
This means:
- Main wind from 180 degrees at 10 knots
- Direction varying between 140 and 220 degrees
Variable wind can create changing crosswind conditions during circuit training.
Calm Wind
00000KT means calm wind.
Calm surface wind does not guarantee calm air at altitude. Wind conditions may be different above the ground.
Visibility Group
In the training example, the visibility group is:
3000
This means the prevailing visibility is 3,000 metres.
Common examples include:
| Code | Meaning |
|---|---|
| 0500 | 500 metres |
| 1500 | 1,500 metres |
| 3000 | 3 kilometres |
| 6000 | 6 kilometres |
| 9999 | 10 kilometres or more |
The code 9999 does not mean unlimited visibility. It means the visibility is at least 10 kilometres.
Directional Visibility
Sometimes visibility may be lower or higher in a particular direction.
A directional group can identify where the reduced visibility exists.
Students should pay particular attention when reduced visibility lies:
- Along the departure path
- Toward the training area
- Near terrain
- On final approach
- Along the planned cross-country route
Runway Visual Range
Runway visual range, or RVR, may be reported when visibility near a runway becomes operationally important.
Example:
R28/1200
This means:
- Runway 28
- RVR is 1,200 metres
Possible tendency letters include:
- U – increasing
- D – decreasing
- N – no significant change
Example:
R28/0800D
This means the RVR for Runway 28 is 800 metres and decreasing.
RVR and general visibility are not the same measurement. RVR relates specifically to the visual range along a runway.
Present Weather
In the example, the present weather group is:
HZ
HZ means haze.
Haze is operationally important in India because it may reduce:
- Horizontal visibility
- Traffic detection
- Landmark recognition
- Horizon definition
- Runway identification
- Visual navigation accuracy
Common METAR Weather Codes
Visibility and Obscuration
| Code | Meaning |
|---|---|
| BR | Mist |
| FG | Fog |
| HZ | Haze |
| FU | Smoke |
| DU | Widespread dust |
| SA | Sand |
| VA | Volcanic ash |
Precipitation
| Code | Meaning |
|---|---|
| RA | Rain |
| DZ | Drizzle |
| SN | Snow |
| SH | Showers |
| GR | Hail |
| GS | Small hail or snow pellets |
Convective and Other Weather
| Code | Meaning |
|---|---|
| TS | Thunderstorm |
| SQ | Squall |
| FC | Funnel cloud or tornado |
| DS | Dust storm |
| SS | Sandstorm |
| FZ | Freezing |
| BL | Blowing |
| DR | Low drifting |
| VC | In the vicinity |
Weather Intensity
A sign before the weather code indicates intensity.
- – means light.
- No sign normally indicates moderate intensity.
- + means heavy.
Examples:
- -RA – light rain
- RA – moderate rain
- +RA – heavy rain
- -TSRA – thunderstorm with light rain
- +TSRA – thunderstorm with heavy rain
- VCTS – thunderstorm in the vicinity
- VCFG – fog in the vicinity
Weather groups may combine several codes.
Example:
TSRA
This means thunderstorm with rain.
Cloud Group
In the training example:
SCT020
This means scattered cloud at 2,000 feet above the aerodrome.
Cloud heights are written in hundreds of feet.
Examples:
- 005 means 500 feet.
- 010 means 1,000 feet.
- 020 means 2,000 feet.
- 100 means 10,000 feet.
Cloud Amount Codes
| Code | Meaning | Approximate coverage |
|---|---|---|
| FEW | Few clouds | 1–2 oktas |
| SCT | Scattered clouds | 3–4 oktas |
| BKN | Broken clouds | 5–7 oktas |
| OVC | Overcast | 8 oktas |
| NSC | No significant cloud | No operationally significant cloud reported |
| VV | Vertical visibility | Sky obscured |
Examples
FEW015
Few clouds at 1,500 feet.
SCT025
Scattered clouds at 2,500 feet.
BKN018
Broken clouds at 1,800 feet.
OVC006
Overcast cloud at 600 feet.
VV002
The sky is obscured, and vertical visibility is 200 feet.
Cloud Ceiling
For operational interpretation, the ceiling is normally associated with the lowest layer reported as:
- Broken
- Overcast
- Vertical visibility
A scattered layer is not normally treated as a ceiling.
Example:
SCT015 BKN025
There are scattered clouds at 1,500 feet and broken clouds at 2,500 feet. The relevant ceiling is 2,500 feet.
Student pilots must compare the ceiling with:
- Training-area requirements
- Circuit altitude
- Terrain
- VFR limits
- School procedures
- Personal weather limits
Cumulonimbus and Towering Cumulus
Two cloud types require special attention:
- CB – cumulonimbus
- TCU – towering cumulus
Example:
FEW025CB
This means a few cumulonimbus clouds with bases at 2,500 feet.
Cumulonimbus clouds may be associated with:
- Thunderstorms
- Lightning
- Heavy rain
- Hail
- Severe turbulence
- Wind shear
- Strong downdrafts
- Microbursts
Example:
SCT030TCU
This means scattered towering cumulus clouds with bases at 3,000 feet.
TCU may indicate developing convective weather and should not be ignored.
Temperature and Dew Point
In the training example:
31/25
This means:
- Temperature: 31°C
- Dew point: 25°C
The difference between the temperature and dew point is called the dew-point spread.
In this example, the spread is 6°C.
A small spread can indicate an increased possibility of:
- Mist
- Fog
- Low cloud
- High humidity
- Reduced visibility
The spread should not be used alone to predict fog. Wind, cloud cover, terrain, moisture, time of day, and forecast conditions must also be considered.
Negative Temperatures
The letter M means minus.
Example:
M03/M07
This means:
- Temperature: minus 3°C
- Dew point: minus 7°C
Negative temperatures are particularly important when assessing icing risk.
QNH
In the training example:
Q1002
This means the QNH is 1002 hectopascals.
The letter Q identifies the pressure setting, while the following four digits give the pressure value.
Other examples include:
- Q0998 – 998 hPa
- Q1008 – 1008 hPa
- Q1013 – 1013 hPa
- Q1021 – 1021 hPa
When the correct QNH is set on the altimeter while the aircraft is on the ground, the altimeter should indicate approximately the aerodrome elevation above mean sea level.
An incorrect pressure setting can produce an incorrect altitude indication.
Students should verify:
- The current QNH
- Correct altimeter setting
- Expected aerodrome elevation
- Any change in pressure during the flight
NOSIG
NOSIG means no significant change is expected during the applicable short trend period.
It does not mean the weather will remain completely unchanged.
Minor changes can still occur. It means that no operationally significant change is forecast according to the applicable criteria.
CAVOK
CAVOK means ceiling and visibility are acceptable under specified aviation-reporting conditions.
It generally indicates:
- Visibility of 10 kilometres or more
- No significant present weather
- No operationally significant low cloud
- No cumulonimbus or towering cumulus requiring reporting
CAVOK does not mean that the sky is completely cloudless.
Recent Weather
Recent significant weather may be shown with the letters RE.
Examples:
- RERA – recent rain
- RETS – recent thunderstorm
- REFG – recent fog
Recent weather means the phenomenon occurred during the relevant period before the observation but was not occurring at the aerodrome at the time of the report.
This information helps pilots understand how quickly conditions may be changing.
Wind-Shear Information
A METAR may contain wind-shear information.
Example:
WS R28
This means wind shear has been reported or forecast in relation to Runway 28.
Another possible form may refer to all runways.
Wind shear is especially dangerous during:
- Take-off
- Initial climb
- Final approach
- Landing
Student pilots should treat wind-shear information seriously, even when the average surface wind appears manageable.
Monsoon METAR Example
Consider another fictional training example:
METAR VOMM 161130Z 16012G22KT 2500 +TSRA SCT012 FEW025CB BKN080 27/24 Q1000
This report can be decoded as follows:
- Routine weather report for Chennai
- Observed on the 16th at 11:30 UTC
- Wind from 160 degrees at 12 knots
- Gusting to 22 knots
- Visibility 2,500 metres
- Heavy thunderstorm rain
- Scattered clouds at 1,200 feet
- Few cumulonimbus clouds at 2,500 feet
- Broken clouds at 8,000 feet
- Temperature 27°C
- Dew point 24°C
- QNH 1000 hPa
This report contains several warning signs:
- Strong gusts
- Reduced visibility
- Heavy rain
- Thunderstorm
- Cumulonimbus cloud
- Small temperature–dew-point spread
A student pilot should not evaluate each group separately. The complete weather picture must be considered.
Winter METAR Example
Consider this fictional example:
METAR VIDP 180230Z 00000KT 0400 R28/0600 FG VV001 09/09 Q1018
This means:
- Delhi weather report
- Observed on the 18th at 02:30 UTC
- Calm wind
- General visibility 400 metres
- Runway 28 RVR of 600 metres
- Fog
- Vertical visibility 100 feet
- Temperature 9°C
- Dew point 9°C
- QNH 1018 hPa
The temperature and dew point are equal, visibility is very low, and the sky is obscured.
These conditions are not suitable for normal student VFR training.
METAR Versus TAF
| Feature | METAR | TAF |
|---|---|---|
| Purpose | Reports observed weather | Forecasts expected weather |
| Time reference | Conditions at observation time | Conditions during validity period |
| Main use | Current weather assessment | Future planning |
| Reliability | Observation of actual conditions | Forecast subject to uncertainty |
| Used alone? | No | No |
A good weather briefing should combine present observations with forecasts and relevant warnings.
METAR Decoding Checklist
Use this checklist whenever reading a METAR:
Identification
- Is it a METAR or SPECI?
- Is the airport code correct?
- Is the report current?
Time
- What is the UTC time?
- What is the corresponding IST?
- Has the calendar date changed?
Wind
- What is the wind direction?
- What is the average speed?
- Are there gusts?
- Is the wind variable?
- What is the crosswind component?
Visibility
- What is the prevailing visibility?
- Is directional visibility included?
- Is RVR reported?
- Is visibility increasing or decreasing?
Weather
- Is there rain, fog, haze, mist, dust, or smoke?
- Is a thunderstorm present or nearby?
- Is the weather light, moderate, or heavy?
Cloud
- What is the lowest cloud layer?
- Is there a broken or overcast ceiling?
- Is CB or TCU reported?
- Is vertical visibility reported?
Temperature and Pressure
- What are the temperature and dew point?
- Is the dew-point spread small?
- What is the current QNH?
Additional Information
- Is recent weather reported?
- Is wind shear mentioned?
- Is a short-term trend included?
- Does a newer SPECI exist?
Common METAR Mistakes
Reading UTC as IST
METAR time is normally written in UTC. Indian pilots must add 5 hours and 30 minutes.
Reading Wind Direction Backwards
Wind direction shows where the wind is coming from.
Ignoring Gusts
The highest gust may be much more operationally important than the average wind speed.
Misreading Cloud Height
BKN020 means broken cloud at 2,000 feet, not 20,000 feet.
Treating SCT as a Ceiling
The operational ceiling is usually based on the lowest BKN, OVC, or VV layer.
Ignoring CB and TCU
These clouds may indicate dangerous convective activity.
Treating 9999 as Unlimited Visibility
It means visibility of 10 kilometres or more.
Looking Only at the METAR
A METAR does not show the complete route forecast or future weather development.
Using an Old Report
Weather may change significantly after the observation time. Always check the report’s age.
Depending Only on Decoded Apps
Decoded information is useful, but students must learn to read the original coded report and verify operational information through approved sources.
Practical Decision-Making for Indian Students
After decoding the METAR, ask:
- Is the visibility suitable for the planned exercise?
- Is the cloud base high enough?
- Is the crosswind within the student limit?
- Are gusts manageable?
- Is thunderstorm activity present?
- Is there fog, haze, dust, or smoke?
- Is the weather improving or worsening?
- Can the aircraft return safely?
- Is the alternate suitable?
- Does the instructor agree with the assessment?
- Are school operating limits satisfied?
Correct decoding is only the first step. Safe interpretation and decision-making are the real objectives.
Key Takeaways
- METAR describes observed weather at an aerodrome.
- METAR groups usually follow a standard order.
- Indian pilots must convert UTC to IST by adding 5 hours and 30 minutes.
- Wind direction shows where the wind is coming from.
- Visibility is usually reported in metres.
- Cloud heights are coded in hundreds of feet.
- BKN, OVC, and VV are important when determining the ceiling.
- CB and TCU require special attention.
- Temperature and dew point help assess atmospheric moisture.
- QNH is used for altimeter setting.
- NOSIG means no significant short-term change is expected.
- A METAR must be combined with forecasts, warnings, aircraft limits, and flying-school procedures.
Frequently Asked Questions
What does METAR mean?
METAR is a standardized coded report of observed weather conditions at an aerodrome.
How often should a student pilot check METAR information?
The student should check the latest report during planning and check again before departure whenever conditions may have changed.
What does Z mean in a METAR?
Z means UTC or Zulu time.
How do Indian pilots convert METAR time to IST?
Add 5 hours and 30 minutes to the UTC time.
What does 9999 mean?
It means the reported prevailing visibility is 10 kilometres or more.
What does SCT020 mean?
It means scattered clouds with a base at 2,000 feet above the aerodrome.
What does BKN015CB mean?
It means broken cumulonimbus cloud with a base at 1,500 feet.
What does Q1012 mean?
It means the reported QNH is 1012 hectopascals.
What does VRB03KT mean?
It means the wind direction is variable at a speed of 3 knots.
What does NOSIG mean?
It means no significant weather change is expected during the applicable short trend period.
What is the difference between METAR and SPECI?
METAR is a routine observation, while SPECI reports specified significant weather changes between routine observations.
Can a pilot make a flight decision using only a METAR?
No. The pilot should also review the TAF, route weather, significant-weather warnings, alternate conditions, fuel planning, aircraft limitations, and operational procedures.
Conclusion
METAR decoding becomes straightforward when students follow the standard reporting sequence. Indian pilot students should regularly practise reading airport identifiers, UTC time, wind, visibility, weather, clouds, temperature, dew point, and QNH. The purpose is not merely to translate codes but to use the information for safe and disciplined flight decisions.
