How to Read a METAR

A METAR looks cryptic until you learn that it follows a predictable sequence.

For example:

METAR KPIT 091955Z COR 22015G25KT 3/4SM R28L/2600FT TSRA OVC010CB 18/16 A2992 RMK SLP045 T01820159

That one line tells you:

• Where the observation was made
• When it was made
• Wind direction, speed, and gusts
• Prevailing visibility
• Runway visual range
• Present weather
• Cloud and ceiling information
• Temperature and dew point
• Altimeter setting
• Additional details in remarks

The important word is observation.

A METAR tells you what was observed at or near a reporting station.

It is not a forecast.

For expected future terminal weather, use a TAF.

What Does METAR Mean?#

In current FAA terminology, METAR is an Aviation Routine Weather Report.

International material also commonly expands METAR as Meteorological Aerodrome Report.

Both usages refer to the standardized coded aviation surface-weather report.

The practical meaning matters more than the expansion:

METAR = observed airport weather

METAR Versus SPECI#

There are two closely related surface observation report types.

METAR#

A METAR is the routine report.

At many aviation weather stations, routine observations are transmitted roughly once each hour.

That does not mean: "Every airport in the world issues exactly one METAR every 60 minutes."

Reporting schedules and capabilities vary by country and station.

SPECI#

A SPECI is a nonroutine special observation issued when specified significant weather changes occur.

In the United States, SPECI criteria include certain changes involving:

• Wind shifts
• Visibility
• Runway Visual Range
• Thunderstorms
• Freezing precipitation
• Snow
• Ceiling
• Tornadoes or funnel clouds

So pilots do not necessarily need to wait for the next routine METAR when important conditions change.

Automated Weather Can Be Newer Than the Latest METAR#

This distinction is easy to miss.

At U.S. airports with ASOS or AWOS, the automated system continually observes weather.

Its voice broadcast can provide approximately one-minute weather.

The transmitted routine METAR may still be the latest scheduled coded report.

That means:

latest METAR ≠ necessarily freshest weather available at the runway

especially at an airport with an operating automated weather broadcast.

METAR Is Standardized—But Not Identical Everywhere#

METAR follows an international ICAO/WMO framework.

But countries are allowed national differences.

That is why pilots encounter variations such as:

So: "METAR is standardized worldwide"

is true.

But: "Every country encodes every element exactly like the United States"

is not.

Basic METAR Order#

A U.S. METAR is organized in this sequence:

1. Report type
2. Station identifier
3. Date and time
4. Modifier, when required
5. Wind
6. Visibility
7. RVR, when reported
8. Weather phenomena
9. Sky condition
10. Temperature/dew point
11. Altimeter setting
12. Remarks

Not every report contains every optional element.

If there is no RVR or significant weather to report, for example, those groups can simply be absent.

1. Report Type#

The report begins with:

METAR

or:

SPECI

Example:

METAR KSEA ...

means a routine aviation weather observation.

SPECI KSEA ...

means a special observation.

Some applications may visually shorten or rearrange displayed data, but when learning the raw format, identify the report type first.

2. Station Identifier#

Next comes the four-letter ICAO code for the weather station.

Examples:

• KJFK — New York JFK
• KORD — Chicago O'Hare
• KSFO — San Francisco

Do not confuse an ICAO location indicator with the three-letter airline/passenger-facing IATA airport code.

For example:

• IATA: JFK
• ICAO: KJFK

See ICAO vs IATA Airport Codes Explained.

Not Every U.S. Airport Starts With K#

For the contiguous 48 states, the familiar three-letter domestic identifier is commonly prefixed with K.

But U.S. ICAO identifiers are not universally Kxxx.

For example:

• Alaska commonly uses PA
• Hawaii commonly uses PH

So: "All U.S. airports start with K"

is incorrect.

3. Date and Time#

The observation time uses:

DDHHMMZ

where:

• DD = day of month
• HH = UTC hour
• MM = UTC minute
• Z = Zulu / UTC

Example:

121851Z

means:

12th day of the month at 18:51 UTC

The month and year are normally known from the surrounding operational context rather than encoded in this group.

Why UTC?#

Aviation crosses:

• Time zones
• States
• Countries
• Continents

Using UTC gives every user the same time reference.

Before using a METAR, check its timestamp.

A perfectly decoded observation can still be operationally misleading if it is old.

4. Modifiers: AUTO and COR#

A modifier may appear after the observation time.

AUTO#

AUTO

means the observation was generated by an automated system without human intervention.

Example:

METAR KSFO 041453Z AUTO ...

When a U.S. automated observation is augmented or backed up by an observer, AUTO is removed.

COR#

COR

means the report corrects an earlier report that contained an error.

Example:

METAR KPIT 091955Z COR ...

A corrected report does not mean the weather changed.

It means the previously transmitted report needed correction.

5. Wind#

A typical wind group looks like:

18012KT

Decode it as:

• 180 — wind from 180°
• 12 — 12 knots
• KT — knots

So:

18012KT

means:

wind from 180° true at 12 knots

METAR Wind Direction Is True#

In U.S. METARs, wind direction is referenced to true north.

This matters because runway numbers and winds spoken by U.S. towers and ATIS are normally referenced to magnetic north.

That distinction becomes important when calculating a crosswind component.

See Crosswind Explained.

Gusts#

A gust is added with G.

Example:

18012G22KT

means:

• Wind from 180°
• Sustained 12 knots
• Gusting 22 knots

The gust is not an additional 22 knots on top of the 12.

It is the reported maximum gust speed.

Calm Wind#

00000KT

means calm wind.

Variable Wind Direction#

At light wind speeds, direction may be encoded as:

VRB03KT

meaning:

variable direction at 3 knots

Another form describes a larger directional variation.

Example:

21010KT 180V240

means:

• Mean wind from 210° at 10 knots
• Direction varied between 180° and 240°

That second group is particularly useful when assessing:

• Crosswind variability
• Runway selection
• Gusty or shifting surface conditions

Wind Is Not the Same as Crosswind#

A 20-knot reported wind is not necessarily a 20-knot crosswind.

Its runway-relative components depend on the angle between:

• Wind direction
• Runway direction

The METAR provides the atmospheric wind observation.

The pilot or flight-planning system determines the runway component.

6. Visibility#

In U.S. METARs, the visibility group reports prevailing visibility in statute miles.

Example:

10SM

means:

10 statute miles visibility

Example:

1/2SM

means:

one-half statute mile

Example:

1 1/2SM

means:

one and one-half statute miles

What "Prevailing Visibility" Means#

Prevailing visibility is not necessarily the farthest object anyone can see in one direction.

At a manual station, it represents the greatest visibility equaled or exceeded throughout at least half of the horizon circle, which need not be continuous.

That makes it a standardized airport observation rather than a claim that visibility is identical in every direction.

10SM Versus P6SM#

This distinction is often taught incorrectly.

In current U.S. METAR practice, automated stations report visibility of 10 miles or greater as:

10SM

The code:

P6SM

means greater than 6 statute miles, but it is primarily a U.S. TAF forecast convention.

So an article about decoding METARs should not teach P6SM as the normal U.S. METAR unlimited-visibility group.

You will see it constantly in TAFs.

See How to Read a TAF.

International Visibility: 9999#

Many international METARs report visibility in meters.

Example:

5000

means:

5,000 meters

9999

means:

10 kilometers or more

It does not mean:

• 9,999 meters exactly
• Infinite visibility
• "Unlimited"

It is the code for visibility meeting or exceeding the upper reporting threshold.

CAVOK#

Many countries also use:

CAVOK

for Ceiling and Visibility OK.

In simplified terms, CAVOK indicates conditions meeting criteria including:

• Visibility at least 10 km
• No significant weather
• No operationally significant low cloud below the applicable threshold
• No cumulonimbus

CAVOK can replace the normal:

• Visibility
• Weather
• Sky-condition

groups.

The United States does not use CAVOK in METARs.

7. Runway Visual Range#

Runway Visual Range, or RVR, is different from prevailing visibility.

RVR estimates how far a pilot can see along a particular runway environment.

Example:

R28L/2600FT

means:

Runway 28 Left RVR 2,600 feet

It is runway-specific.

Prevailing visibility is an airport weather observation.

RVR is specifically tied to visual range along the runway.

For the deeper operational distinction, see Runway Visual Range (RVR).

Variable RVR#

Example:

R27R/M1000V4000FT

indicates variable RVR on Runway 27 Right from:

• Less than 1,000 feet
• To 4,000 feet

M means below the system's reportable minimum.

P can indicate a value above the system's reportable maximum.

RVR can be critical to instrument approach and departure operations even when the general airport visibility group tells a different story.

8. Present Weather#

Weather phenomena appear after visibility and RVR.

Rather than memorizing random abbreviations, learn their structure.

A weather group can combine:

1. Intensity or proximity
2. Descriptor
3. Precipitation or obscuration
4. Other phenomena

Intensity#

Common prefixes include:

• - — light
• no sign — moderate
• + — heavy

Examples:

-RA

= light rain

RA

= moderate rain

+RA

= heavy rain

Common Precipitation Codes#

Common Descriptors#

Descriptors are commonly combined with the phenomenon they describe.

For example:

SHRA

means rain showers.

FZRA

means freezing rain.

FZDZ

means freezing drizzle.

BLSN

means blowing snow.

Thunderstorms#

TSRA

means:

thunderstorm with rain

+TSRA

means:

thunderstorm with heavy rain

The + describes the precipitation intensity rather than a formal "heavy thunderstorm category."

VCTS

means:

thunderstorm in the vicinity

The thunderstorm is near the station rather than necessarily directly over it.

Obscurations#

Common visibility-obscuring phenomena include:

For example:

3SM BR

means:

3 statute miles visibility with mist

Vicinity#

VC

means the phenomenon is in the vicinity of the airport.

Examples include:

VCTS

= thunderstorm in vicinity

VCSH

= showers in vicinity

Do not read VC as an intensity.

It describes location relative to the station.

What About RE for Recent Weather?#

Some international METAR implementations can use RE for recent weather.

Current U.S. practice generally does not use a body RE group that way.

Instead, U.S. remarks can encode beginning and ending times.

Example:

RAE42

means:

rain ended at 42 minutes past the hour

SNB42

means:

snow began at 42 minutes past the hour

This is a good example of why U.S. and international METAR conventions should not be treated as perfectly interchangeable.

9. Sky Condition#

Cloud groups describe:

• Cloud amount
• Cloud-base height
• Certain cloud types

Common amounts are:

Cloud Height#

The three digits after the coverage code represent cloud-base height in hundreds of feet above ground level.

Example:

SCT020

means:

scattered clouds at 2,000 feet AGL

BKN025

means:

broken clouds at 2,500 feet AGL

OVC010

means:

overcast at 1,000 feet AGL

The AGL reference is important.

These are not cloud-base altitudes above mean sea level.

What Is a Ceiling?#

A ceiling is the lowest:

• Broken layer
• Overcast layer
• Vertical visibility into an obscuration

So:

FEW008 SCT020 BKN035

has a ceiling of:

3,500 feet AGL

because the first ceiling-producing layer is BKN035.

FEW and SCT are not ceilings.

Vertical Visibility#

Sometimes the sky cannot be meaningfully divided into cloud layers because a surface-based obscuration blocks the view upward.

Example:

VV006

means:

vertical visibility 600 feet

That is an indefinite ceiling of 600 feet.

This is why the rule: "Ceiling is only the lowest BKN or OVC"

is incomplete.

Vertical visibility can also establish the ceiling.

SKC Versus CLR#

In U.S. observations:

SKC

means sky clear at a manual station.

CLR

is used by automated systems when no clouds are detected at or below 12,000 feet.

That wording matters.

CLR does not prove there are no clouds anywhere in the sky above 12,000 feet.

CB and TCU#

Two important convective cloud types can be appended to cloud groups.

CB#

OVC010CB

means:

overcast cumulonimbus with a base at 1,000 feet AGL

TCU#

SCT025TCU

means:

scattered towering cumulus at 2,500 feet AGL

CB and TCU can provide valuable clues about active or developing convection.

10. Temperature and Dew Point#

Temperature and dew point appear as:

TT/DD

Example:

23/14

means:

• Temperature 23°C
• Dew point 14°C

The values are reported in Celsius.

Negative Temperatures#

M before the number means minus.

Example:

M05/M08

means:

• Temperature −5°C
• Dew point −8°C

Here M means minus.

Elsewhere in aviation weather coding, M can have other contextual meanings—for example "less than" in certain visibility or RVR groups.

Read the code in context.

Temperature-Dew Point Spread#

A shrinking temperature-dew point spread indicates increasing relative humidity.

That can raise concern for:

• Fog
• Low cloud
• Saturation

But there is no meteorological switch at exactly:

• 3°C
• 5°C
• Any other fixed spread

that guarantees fog.

Fog formation also depends on:

• Cooling
• Wind
• Moisture
• Terrain
• Cloud cover
• Air-mass movement

Treat the spread as a clue.

Can You Get Density Altitude From a METAR?#

The raw METAR generally does not contain a group that simply says: "Density altitude 6,800 feet."

But it gives important inputs for calculating density altitude, especially:

• Temperature
• Altimeter setting

combined with the airport elevation.

For the actual calculation and aircraft-performance implications, see Density Altitude Explained.

11. Altimeter Setting#

In U.S. METARs, the altimeter group begins with A.

Example:

A2992

means:

29.92 inches of mercury

Example:

A3012

means:

30.12 inHg

The decimal point is implied.

International QNH#

Many international METARs instead use a Q group.

Example:

Q1013

means:

QNH 1013 hPa

This is one of the most obvious national differences a U.S.-trained reader sees when decoding METARs overseas.

Altimeter Setting Is Not the Same as Sea-Level Pressure Remark#

A U.S. METAR may also contain sea-level pressure in the remarks.

Example:

SLP045

decodes to:

1004.5 hPa sea-level pressure

That is not another way of writing A2992.

The altimeter setting and meteorological sea-level pressure are related pressure values used for different purposes.

12. Remarks#

RMK

marks the beginning of the remarks section.

Remarks can contain information that is extremely useful operationally.

The mistake is treating everything after RMK as optional trivia.

AO1 and AO2#

At U.S. automated stations:

AO1

means the automated station does not have a precipitation discriminator.

AO2

means it does have a precipitation discriminator capable of distinguishing precipitation characteristics such as liquid versus frozen/freezing precipitation.

Example:

RMK AO2

therefore tells you something about the observing system's capability.

Peak Wind#

A remark beginning:

PK WND

reports a peak wind event.

This can add important context when the ordinary wind group does not tell the full recent story.

Wind Shift#

WSHFT

identifies a significant wind shift.

That can matter around:

• Frontal passage
• Convective outflow
• Rapid runway-condition changes

A METAR does not usually say: "Cold front passed."

Instead, pilots infer the larger meteorological explanation by comparing observations and broader weather products.

See Air Masses & Fronts in Aviation.

Exact Temperature and Dew Point#

The body rounds temperature and dew point to whole degrees Celsius.

Remarks can provide values to tenths.

Example:

T01820159

means:

• Temperature 18.2°C
• Dew point 15.9°C

That can matter when precise meteorological analysis is needed.

Sea-Level Pressure#

As above:

SLP045

means:

1004.5 hPa

The three-digit value is reconstructed into a plausible sea-level pressure by adding the appropriate leading 9 or 10.

For ordinary pilot decoding, weather applications usually do this automatically.

A Full FAA-Style Example#

Consider:

METAR KPIT 091955Z COR 22015G25KT 3/4SM R28L/2600FT TSRA OVC010CB 18/16 A2992 RMK SLP045 T01820159

Decode it from left to right.

METAR#

Routine aviation weather observation.

KPIT#

Pittsburgh International Airport.

091955Z#

9th day of the month at 19:55 UTC.

COR#

Corrected observation.

22015G25KT#

Wind:

• From 220° true
• 15 knots sustained
• Gusting 25 knots

3/4SM#

Prevailing visibility:

three-quarters of a statute mile

R28L/2600FT#

Runway 28 Left RVR:

2,600 feet

TSRA#

Thunderstorm with rain.

OVC010CB#

Overcast cumulonimbus at:

1,000 feet AGL

This is the ceiling.

18/16#

• Temperature 18°C
• Dew point 16°C

A2992#

Altimeter:

29.92 inHg

RMK#

Remarks begin.

SLP045#

Sea-level pressure:

1004.5 hPa

T01820159#

Precise:

• Temperature 18.2°C
• Dew point 15.9°C

That is far more information than simply: "The weather is bad."

It describes a low-ceiling, low-visibility thunderstorm environment with gusty winds and reduced RVR.

Automated METAR Example#

Now decode:

METAR KSFO 041453Z AUTO VRB02KT 3SM BR CLR 15/12 A3012 RMK AO2

METAR#

Routine observation.

KSFO#

San Francisco International Airport.

041453Z#

4th day at 14:53 UTC.

AUTO#

Fully automated observation without human intervention.

VRB02KT#

Variable wind at 2 knots.

3SM#

Visibility 3 statute miles.

BR#

Mist.

CLR#

Automated station detects no clouds at or below 12,000 feet.

15/12#

Temperature 15°C, dew point 12°C.

A3012#

Altimeter 30.12 inHg.

RMK AO2#

Automated station with a precipitation discriminator.

This example also demonstrates why:

CLR

does not mean:

perfectly clear sky at every altitude.

It describes what the automated sensor can report.

International-Style Example#

Consider:

METAR LIRP 222315Z 06004KT CAVOK 22/16 Q1014 NOSIG

This illustrates several international differences.

LIRP#

ICAO station identifier.

222315Z#

22nd day at 23:15 UTC.

06004KT#

Wind from 060° at 4 knots.

CAVOK#

Visibility, significant weather, and cloud conditions satisfy the applicable CAVOK criteria.

22/16#

Temperature 22°C, dew point 16°C.

Q1014#

QNH 1014 hPa.

NOSIG#

No significant change expected in the applicable short-term trend period.

CAVOK, Q1014, and NOSIG are the sort of groups a U.S.-focused pilot may encounter when reading international reports.

Flight Category Is Derived—Not Encoded#

A raw METAR does not contain:

VFR

MVFR

IFR

or:

LIFR

as its normal flight-category group.

Those are derived categories based on the reported:

• Ceiling
• Visibility

A weather website may calculate and color-code the station for you.

That does not mean the category was transmitted in the raw METAR.

Common U.S. Flight Categories#

The commonly used U.S. categories are:

Use the more restrictive of ceiling or visibility.

These categories are useful weather summaries.

They are not a substitute for:

• Actual VFR cloud-clearance regulations
• Instrument approach minimums
• Alternate requirements
• Operator procedures

A flight category is a derived weather classification.

It is not itself the full legal operating rule.

Why BKN025 10SM Is MVFR#

Suppose a METAR contains:

10SM BKN025

Visibility:

10 SM

Ceiling:

2,500 ft AGL

Under the common U.S. flight-category scheme, the 2,500-foot ceiling puts the observation in:

MVFR

even though visibility is excellent.

So: "2,500-foot ceiling is well above VFR minimums"

is not a correct flight-category interpretation.

It may still permit particular VFR operations depending on:

• Airspace
• Cloud clearance
• Route
• Terrain
• Pilot and aircraft requirements

But the weather-station category itself is MVFR.

Visibility Is Not the Same as VFR Legal Minimums#

Another common mistake is memorizing: "VFR means 3 miles and a 1,000-foot ceiling."

That is not the definition of the VFR flight category, nor is it a universal statement of U.S. VFR weather minima.

Actual VFR requirements depend on:

• Airspace
• Altitude
• Day or night in some cases
• Distance from clouds
• Other regulations

Do not mix:

weather-display flight category

with:

regulatory VFR minimums.

How Pilots Should Actually Read a METAR#

Decoding individual groups is only step one.

The more useful process is:

1. Check location#

Am I reading the correct station?

2. Check time#

How old is the observation?

3. Look at the wind#

Consider:

• Direction
• Sustained speed
• Gusts
• Variability
• Crosswind implications

4. Check visibility and RVR#

Ask:

• What is prevailing visibility?
• Is RVR being reported?
• Does the approach depend on RVR?

5. Identify significant weather#

Look especially for:

• Thunderstorms
• Freezing precipitation
• Heavy precipitation
• Fog
• Snow
• Blowing phenomena

6. Find the ceiling#

Do not just read the lowest cloud layer.

Find the lowest:

• BKN
• OVC
• VV

layer.

7. Check temperature and dew point#

Think about:

• Fog potential
• Icing environment
• Density altitude
• Surface conditions

8. Check altimeter#

Use the appropriate current setting according to the operation.

9. Read the remarks#

Do not automatically stop at RMK.

10. Compare with other observations#

One METAR is much more useful when placed into a trend.

METAR Trends Matter#

Consider several observations from the same airport:

• Wind gradually strengthens
• Pressure falls
• Ceiling lowers
• Visibility deteriorates
• Rain begins
• Wind suddenly shifts
• Temperature falls
• Pressure begins rising

That can reveal the passage of a larger weather system.

The METAR did not explicitly say: "A cold front has arrived."

The trend tells a story.

This is why repeatedly checking one airport's observations can be more informative than decoding one isolated report perfectly.

METAR Is a Point Observation#

A METAR describes conditions at a reporting station.

It does not tell you everything about:

• The route
• Mountains nearby
• Conditions 30 miles away
• Cloud tops
• Icing aloft
• Turbulence aloft
• Thunderstorms beyond the observation area

A perfectly good METAR at departure does not prove the route is safe.

Automated Sensor Limitations#

Automated observing systems are powerful but not omniscient.

For example, an unaugmented automated station can have limitations involving:

• Clouds above sensor-reporting height
• Weather phenomena the sensor cannot identify
• Spatial representativeness
• Local visibility differences

That is one reason the:

• AUTO
• AO1
• AO2

information matters.

Human augmentation can add observations that automation alone may not provide.

METAR Versus TAF#

The simplest distinction is:

METAR = observed

TAF = forecast

A METAR might say:

BKN008

now.

The TAF may forecast:

FM1800 SCT025

later.

Neither replaces the other.

See How to Read a TAF for forecast change groups such as:

• FM
• TEMPO
• PROB

METAR and Crosswind Planning#

A METAR can provide:

• Wind direction
• Sustained wind speed
• Gust speed

Those values can be used to estimate runway-relative wind components.

But remember the U.S. reference issue:

METAR wind = true

while runway designators and tower/ATIS winds are magnetic.

See Crosswind Explained.

METAR and Density Altitude#

METAR temperature and altimeter setting are useful inputs for density-altitude planning.

But aircraft performance requires more than weather decoding.

You still need:

• Airport elevation
• Aircraft weight
• Runway
• Wind
• AFM/POH performance data

See Density Altitude Explained.

METAR and Icing#

A surface METAR can provide useful clues such as:

• Temperature
• Dew point
• Freezing precipitation
• Cloud
• Precipitation

But it does not describe the complete three-dimensional icing environment.

Use current icing forecasts, PIREPs, and aircraft-specific limitations.

See Aircraft Icing Explained.

METAR and Thunderstorms#

Codes such as:

• TS
• TSRA
• VCTS

tell you that convective weather is being observed at or near the station.

But one airport observation cannot describe the full thunderstorm field.

Use:

• Radar
• SIGMETs
• Convective products
• PIREPs
• Current ATC/dispatch information

as appropriate.

METAR and Enroute Hazards#

METAR is one piece of a weather briefing.

For enroute planning, also consider relevant:

• SIGMETs
• G-AIRMETs or AIRMETs where applicable
• PIREPs
• Radar
• Satellite imagery
• Turbulence guidance
• Icing guidance
• Forecasts

A METAR answers:

What is being observed here?

It does not answer every weather question for the flight.

Common METAR Mistakes#

Reading a METAR as a forecast#

It is an observation.

Assuming every station reports exactly hourly#

Routine reports are commonly hourly, but station schedules and capabilities vary.

Ignoring a SPECI#

The special observation may contain the most important recent change.

Forgetting AUTO#

Automated observations have defined capabilities and limitations.

Mixing true METAR wind with magnetic runway heading#

Convert to the same reference when precision matters.

Treating P6SM as the normal U.S. METAR visibility code#

P6SM is primarily seen in U.S. TAFs.

U.S. automated METARs normally report 10 miles or greater as 10SM.

Treating 9999 as unlimited visibility#

It means 10 km or more.

Treating RVR as another name for prevailing visibility#

RVR is runway-specific.

Calling SCT a ceiling#

Scattered cloud is not a ceiling.

Forgetting vertical visibility#

VV can define an indefinite ceiling.

Assuming CLR means no clouds anywhere#

At an automated U.S. station, it means no clouds detected at or below 12,000 feet.

Using one temperature-dew point threshold as a fog guarantee#

Fog depends on more than spread alone.

Stopping at RMK#

Remarks can contain operationally useful information.

Treating VFR/MVFR/IFR/LIFR as raw METAR codes#

They are derived categories.

Treating flight category as the same thing as legal VFR or approach minima#

It is not.

Frequently Asked Questions#

Key Takeaways#

• A METAR is an aviation surface-weather observation, not a forecast.
• Current FAA terminology calls METAR an Aviation Routine Weather Report.
• SPECI is a nonroutine special report triggered by specified significant weather changes.
• Routine METARs are commonly transmitted about once an hour, but reporting cadence varies.
• ASOS/AWOS voice weather can be newer than the latest routine METAR.
• METAR uses a standardized international framework, but national differences remain.
• A U.S. METAR is ordered as report type, station, time, modifier, wind, visibility, RVR, weather, sky condition, temperature/dew point, altimeter, and remarks.
• AUTO identifies a fully automated report without human intervention; COR identifies a corrected report.
• U.S. METAR wind direction is referenced to true north.
• U.S. tower, ATIS, and ASOS/AWOS voice winds are magnetic.
• G identifies gust speed; 00000KT means calm; VRB identifies variable direction.
• U.S. METAR visibility is reported in statute miles.
• P6SM is mainly a U.S. TAF convention rather than the normal U.S. METAR high-visibility group.
• 9999 in many international reports means visibility of 10 km or greater.
• CAVOK is used internationally by many States but is not used in U.S. METARs.
• RVR is runway-specific and is not the same as prevailing visibility.
• Weather codes combine qualifiers, descriptors, precipitation, obscuration, and other phenomena.
• Cloud bases in METARs are reported in hundreds of feet AGL.
• FEW and SCT do not constitute ceilings.
• The ceiling is the lowest BKN or OVC layer or vertical visibility into an obscuration.
• CLR at a U.S. automated station means no clouds detected at or below 12,000 feet.
• CB and TCU identify cumulonimbus and towering cumulus.
• Temperature and dew point are reported in Celsius.
• A shrinking temperature-dew point spread can indicate increasing saturation risk but does not guarantee fog.
• U.S. altimeter groups use inches of mercury, such as A2992; many international reports use QNH groups such as Q1013.
• Remarks can include observing-system type, peak wind, wind shifts, precise temperature, sea-level pressure, and other useful information.
• VFR, MVFR, IFR, and LIFR are derived from ceiling and visibility rather than transmitted as normal raw METAR groups.
• Flight category is not the same thing as regulatory VFR minima or instrument approach minima.
• A METAR describes one reporting location at one time; it does not describe the complete route.
• Comparing a sequence of METARs often reveals more than reading a single observation in isolation.
• Current observations, TAFs, PIREPs, radar, advisories, and other weather products should be interpreted together.

Sources & References#

• FAA Aeronautical Information Manual, current edition, Chapter 7: METAR/SPECI format, surface observations, visibility, cloud heights, RVR, automated observations, and remarks.
• FAA Aviation Weather Handbook, FAA-H-8083-28B, Chapter 24: Observations, including METAR and SPECI.
• FAA Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25C, Chapter 13: Aviation Weather Services.
• Federal Meteorological Handbook No. 1, Surface Weather Observations and Reports, 2019 edition: U.S. observing and METAR/SPECI coding standards.
• NOAA/NWS Aviation Weather Center: METAR data, decoding guidance, flight-category displays, and current observations.
• U.S. Aeronautical Information Publication, GEN 1.7: notified U.S. differences from ICAO meteorological standards.
• ICAO Annex 3, Meteorological Service for International Air Navigation, 21st Edition, August 2025, for the international meteorological framework and national implementation context.