How to Read METARs and TAFs

Aviation weather can feel like learning a second language. A student pilot opens a weather briefing and finds a line such as 18012G20KT 3SM -RA BKN012. There are no complete sentences, almost no punctuation, and plenty of abbreviations. Yet that short string contains information that can affect runway selection, visibility, terrain clearance, and whether a flight should launch at all.

The good news is that weather reports are highly structured. Once you understand the order of the fields, you can read most routine reports without memorizing every possible abbreviation. More importantly, you can stop thinking of a METAR as a puzzle to solve and start thinking of it as evidence about the flying environment.

This guide explains what METARs and TAFs tell you, how to decode their most useful groups, what the codes do not tell you, and how to apply the information to real decisions. The examples below are invented for instruction. They are not current weather reports and must not be used for flight planning.

First, Understand the Difference

A METAR reports observed weather at an aerodrome. It describes conditions measured or observed at a particular time. A TAF, or Terminal Aerodrome Forecast, describes expected conditions at an aerodrome during a specified future period. The two products use much of the same vocabulary but answer different questions.

If you're departing at 1900Z, a METAR observed at 1853Z can help describe conditions near departure. A TAF issued earlier may tell you whether the airport is expected to deteriorate after sunset. Neither replaces a full briefing. A METAR is geographically limited; a TAF is a forecast, not a promise. Weather between airports, above the reporting level, or along a route may be very different.

A useful mental model is: METAR = observed snapshot; TAF = forecast timeline. Compare the forecast with recent observations, look for trends, and seek additional information where uncertainty matters.

How to Read a METAR From Left to Right

Consider this illustrative report:

METAR KABC 151853Z 24008G15KT 10SM FEW025 BKN060 22/14 A2992 RMK AO2

Read it in sequence: report type, station, observation time, wind, visibility, weather (if present), sky conditions, temperature/dew point, altimeter, and remarks. Not every report includes every group. When no reportable phenomenon exists, the corresponding group may simply be absent.

The Station Identifier and Timestamp

KABC is a fictional four-letter station identifier. Many locations in the contiguous United States use a leading K, but do not assume every station worldwide follows that convention. 151853Z means the observation was taken on the 15th day of the month at 1853 UTC. The report does not encode the month or year in that group, so use the surrounding briefing context and report date.

Zulu time is UTC. Aviation uses it to reduce confusion between time zones and daylight saving changes. If you're planning around a sunset, arrival, or fuel stop, convert carefully. A report from the previous hour may be less representative during fast-changing conditions than one observed minutes ago.

A SPECI is a special report issued when qualifying conditions change; it is not simply another name for a scheduled METAR. AUTO indicates an automated report without human augmentation. COR indicates a correction. Pay attention to these markers because they describe how the report was produced or updated.

Wind: Direction, Speed, and Gusts

24008G15KT means wind from 240 degrees true at 8 knots, gusting to 15 knots. The first three digits give the direction from which the wind blows, the next digits the sustained speed, and G15 the gust speed. KT stands for knots.

A pilot approaching a runway does not only care about the overall speed. The crosswind and tailwind components matter. Wind directly down the runway is different from the same wind blowing across it. For a rough illustration, a 20-knot wind 30 degrees off the runway heading produces approximately 10 knots of crosswind; this is an approximation, not a substitute for the aircraft's performance guidance.

00000KT indicates calm wind. VRB03KT indicates variable direction at 3 knots. A separate direction-variation group such as 180V240 can appear when the wind direction varies across a qualifying range. If the wind is gusty or variable, ask what that means for your particular runway, airplane, and proficiency—not merely whether it is below a published maximum.

Important distinction: wind direction in METARs is referenced to true north. Wind direction transmitted by ATC for runway operations is generally referenced to magnetic north. Mixing the two can introduce errors in mental crosswind estimates, especially where magnetic variation is large.

Visibility: What 10SM Really Means

10SM reports prevailing visibility of 10 statute miles or more in a U.S. METAR. It does not mean that every direction has identical visibility, nor does it guarantee that the route beyond the airport is clear. 3SM is three statute miles. Fractions such as 1/2SM indicate reduced visibility. In U.S. reports, M1/4SM can indicate visibility less than one-quarter mile.

Visibility can be affected by precipitation, fog, haze, smoke, dust, or other obscurations. A report of good surface visibility also says little by itself about clouds that may block a climb or descent. That is why visibility and sky condition must be read together.

For instrument operations, runway visual range (RVR) may be reported separately, for example in a group beginning with R followed by a runway identifier. RVR is not interchangeable with prevailing visibility. Its operational use depends on the applicable procedure and requirements.

Present Weather: Intensity and Phenomena

Weather groups often look cryptic until you split them into components. -RA means light rain; RA without an intensity marker means moderate rain; +RA means heavy rain. SN means snow, BR mist, FG fog, HZ haze, and TS thunderstorm. A compound code such as TSRA means thunderstorm with rain; SHRA means rain showers.

Do not treat all visibility reductions alike. Mist, fog, smoke, and precipitation have different causes and can behave differently over time. In particular, thunderstorms create hazards far beyond the visibility reported at an airport: turbulence, wind shear, lightning, hail, and rapidly changing conditions may exist nearby. A single METAR cannot map an entire convective system.

If a weather code is unfamiliar, look it up in the AIM's key to METAR and TAF codes rather than guessing. Learning the most common combinations first is more useful than trying to memorize the complete code table in one sitting.

Clouds: FEW, SCT, BKN, and OVC

Cloud groups combine coverage and base height. FEW025 means a few clouds at 2,500 feet above ground level. SCT040 means scattered clouds at 4,000 feet AGL. BKN060 means broken clouds at 6,000 feet AGL. OVC008 means overcast at 800 feet AGL.

The coverage codes represent approximate portions of the sky: few is more than zero through two eighths; scattered is three to four eighths; broken is five to seven eighths; and overcast is eight eighths. The number is in hundreds of feet, so 012 is 1,200 feet, not 12,000.

The ceiling is generally the height of the lowest broken or overcast layer, or the vertical visibility into an obscuration when applicable. A scattered layer is not a ceiling. In our sample report, FEW025 BKN060, the reported ceiling is 6,000 feet AGL, not 2,500 feet. That difference is essential when evaluating flight categories, approaches, and VFR operations.

VV003 reports vertical visibility of 300 feet into an obscuration. In an automated report, CLR does not necessarily mean a cloudless sky to unlimited altitude; it generally means no clouds detected below the automated system's reporting limit. A pilot looking outside may see higher cloud layers that the automated station does not report.

Cloud bases in an airport METAR are AGL, while your aircraft altimeter ordinarily displays altitude referenced to MSL when set correctly. If the airport elevation is 1,500 feet MSL and the reported ceiling is 2,000 feet AGL, the approximate ceiling altitude is 3,500 feet MSL. This is a useful conceptual conversion, but terrain and cloud bases can vary away from the airport.

Temperature and Dew Point

22/14 means air temperature 22°C and dew point 14°C. The dew point is the temperature to which air must cool, under the relevant conditions, to become saturated. A small temperature–dew point spread can suggest an increased possibility of low clouds or fog if cooling continues, but it does not independently predict whether fog will form.

Negative temperatures are preceded by M, for minus: M02/M05 means minus 2°C and minus 5°C. Temperature matters for aircraft performance, icing considerations, and weather trends. The dew point helps you think about moisture, but always consider wind, cloud cover, terrain, and the broader weather pattern.

Altimeter Setting

A2992 means an altimeter setting of 29.92 inches of mercury. The leading A is the U.S. inches-of-mercury format; the digits imply a decimal point after the first two. Some other regions use Q groups in hectopascals.

A correct altimeter setting helps your instrument indicate altitude appropriately. A setting error can create a meaningful altitude error. The familiar approximation of roughly 1,000 feet per inch of mercury is useful for recognizing the scale of the risk, but operational altimetry procedures and temperature-related errors require more care.

Remarks: Useful, but Don't Drown in Them

RMK begins the remarks section. AO2 identifies an automated station equipped with a precipitation discriminator. Other remarks can provide sea-level pressure, more precise temperature, precipitation totals, cloud types, lightning information, and other details.

You do not have to decode every remark before understanding the basic conditions. Learn the body of the report first, then examine remarks that affect your flight. If a report is unusual, remarks can explain what the basic groups leave out.

A Second METAR: When the Report Should Get Your Attention

Now try this fictional example:

METAR KXYZ 160045Z 17018G28KT 2SM +RA BR BKN007 OVC020 18/17 A2976

Start with the big picture. Winds are from 170° true at 18 knots, gusting to 28. Prevailing visibility is two statute miles. Heavy rain and mist are reported. The lowest broken layer is 700 feet AGL, making the ceiling 700 feet. Temperature and dew point are close, and the altimeter setting is 29.76.

Even before consulting a flight-category display, you should recognize several concerns: reduced visibility, a low ceiling, gusty wind, and precipitation. For a VFR pilot, this is not a situation to reduce to one simple question such as, “Is two miles enough?” The airspace, applicable minimums, route, terrain, and pilot capabilities all matter. The presence of low ceilings and heavy rain should prompt careful consideration of whether the flight is appropriate at all.

For an IFR pilot, legal instrument privileges do not eliminate weather-related risk. Crosswind performance, approach minimums, missed-approach planning, alternate requirements, icing and convection, and runway conditions may all matter. The METAR tells you what was observed at one place and time—not what the entire approach will feel like.

What a TAF Adds to the Picture

A TAF is a forecast for an aerodrome, not a weather observation. It typically includes the station, issuance time, validity period, and one or more forecast groups. U.S. TAFs commonly cover 24 or 30 hours, depending on the airport. They are issued on a schedule and may be amended when warranted.

Consider this fictional TAF:

TAF KABC 151720Z 1518/1618
  24008KT P6SM SCT030
  FM160200 19006KT P6SM BKN015
  TEMPO 1604/1608 3SM BR BKN008
  FM161500 25010KT P6SM SCT025

151720Z is the issuance time: the 15th at 1720 UTC. 1518/1618 is the forecast validity period: from 1800 UTC on the 15th through 1800 UTC on the 16th. This distinction is easy to miss. The issuance time is not the beginning of every forecast condition.

The initial forecast calls for wind from 240° at 8 knots, visibility greater than six statute miles (P6SM), and scattered clouds at 3,000 feet AGL. The forecast then changes at 0200Z on the 16th.

FM: A New Prevailing Set of Conditions

FM160200 means from 0200Z on the 16th. It introduces a new prevailing forecast: wind from 190° at 6 knots, visibility greater than six miles, and broken clouds at 1,500 feet AGL.

The practical interpretation is not simply “the clouds get lower.” A scattered layer has become a broken layer, so a ceiling is now forecast. That could materially affect VFR planning and some instrument operations. The change is particularly relevant if you expect to return after dark.

A later FM161500 indicates conditions forecast from 1500Z on the 16th: wind from 250° at 10 knots, visibility greater than six miles, and scattered clouds at 2,500 feet AGL.

TEMPO: Temporary Fluctuations

TEMPO 1604/1608 3SM BR BKN008 forecasts temporary conditions between 0400Z and 0800Z on the 16th: three miles visibility in mist and a broken ceiling at 800 feet. The word “temporary” does not mean harmless. A short period of poor conditions can still coincide with your arrival or departure.

TEMPO groups represent fluctuations expected to last less than an hour at a time and, in total, less than half of the stated period under the standard U.S. convention. Do not read them as a guarantee that the worse conditions will occur at a convenient time—or that you can safely ignore them.

PROB and Other Change Groups

Some TAFs contain probability groups such as PROB30, which indicate a stated probability of specified conditions during a period. U.S. civilian TAF conventions restrict when certain groups are used; do not assume every international TAF follows exactly the same practices. Other jurisdictions may use BECMG for conditions becoming established over a period. U.S. National Weather Service TAFs generally do not use BECMG groups.

A common decoding mistake is to treat every forecast group as an independent report. Some groups replace the prevailing conditions, while others describe temporary or probabilistic changes. Read the forecast as a timeline and understand which conditions carry forward.

Put the METAR and TAF Together

Imagine you are preparing to depart at 2300Z and return at 0500Z. The current METAR shows excellent visibility and scattered clouds. The TAF, however, forecasts a broken layer at 1,500 feet beginning at 0200Z, with temporary mist and an 800-foot ceiling possible between 0400Z and 0800Z.

A pilot who reads only the current METAR may conclude that the weather is good. A pilot who reads the forecast sees a potentially very different arrival environment. The important question becomes whether the aircraft, pilot, route, destination, and available alternatives make the planned return reasonable.

Now imagine the reverse: the current METAR reports low ceilings, while the TAF predicts improvement. A forecast of better weather does not mean it has arrived. Look at subsequent observations and broader meteorological evidence before relying on the improvement.

This is the central skill: use observations to establish what is happening, forecasts to understand what may happen, and other weather products to understand what is happening between the reporting points.

Three Common Traps That Create Bad Decisions

Trap one: confusing ceiling with the lowest cloud layer. FEW010 BKN035 does not report a 1,000-foot ceiling. The reported ceiling is 3,500 feet AGL. Yet the few clouds at 1,000 feet might still matter to your route or maneuvering. Correctly decoding the ceiling does not make lower clouds irrelevant.

Trap two: confusing AGL and MSL. Airport cloud bases in METARs and TAFs are AGL. Sectional-chart elevations and aircraft indicated altitudes are generally expressed with respect to MSL. An aircraft at 3,000 feet MSL over an airport at 2,000 feet MSL is only about 1,000 feet above that airport. In mountainous terrain, the ground elevation changes rapidly, so a cloud-base conversion at one airport may not describe the terrain along the route.

Trap three: reading a TAF as certainty. Forecasts are estimates of future conditions. They can be amended, and actual weather may differ. If the safe completion of a flight depends on one precise improvement occurring on schedule, your plan has little resilience.

A fourth trap deserves mention: assuming “VFR conditions” means a flight is wise. Weather flight categories are broad descriptors; they do not incorporate every regulatory minimum, terrain hazard, aircraft limitation, or personal minimum.

A Quick Reference Table

Practice: Decode Before Reading the Answer

Exercise 1

METAR KQRS 161955Z 30012G19KT 6SM HZ SCT020 BKN045 27/12 A3004

What is the wind? Is there a ceiling? Is visibility unlimited?

Answer: Wind is from 300° true at 12 knots gusting to 19. The ceiling is 4,500 feet AGL because the broken layer is the lowest ceiling-defining layer. Visibility is six statute miles in haze, not unlimited. The temperature is 27°C, dew point 12°C, and altimeter setting 30.04 inches Hg.

Exercise 2

TAF KQRS 161720Z 1618/1718
  30010KT P6SM SCT035
  FM170300 12005KT 4SM BR BKN012
  FM171400 28008KT P6SM SCT025

When is the lower ceiling forecast? What changes later?

Answer: From 0300Z on the 17th, the prevailing forecast calls for four-mile visibility in mist and a broken ceiling at 1,200 feet AGL. From 1400Z, it calls for wind from 280° at 8 knots, visibility greater than six miles, and scattered clouds at 2,500 feet AGL. Those are forecast changes, not observations.

Exercise 3

You plan a VFR trip to an airport with a current report of 10SM SCT020, but its TAF includes TEMPO for a broken 900-foot layer near your expected arrival. Should you ignore the TEMPO group because the current METAR is good?

Answer: No. The current observation and forecast describe different times and types of information. Investigate the timing, confidence, route weather, terrain, available alternatives, and your personal minimums. A temporary low ceiling may still coincide with arrival. There is no safe universal go/no-go answer from those two groups alone.

Frequently Asked Questions

Does a METAR Show the Weather Right Now?

It shows weather observed at the stated time. During rapidly changing conditions, even a recent report may be out of date by the time you read it. Always check its timestamp and look for more recent special reports or observations.

Why Does a TAF Say P6SM Instead of 10SM?

U.S. TAFs commonly use P6SM to express forecast visibility greater than six statute miles. That is a forecast coding convention, not a statement that visibility is exactly six miles.

Are METAR Winds True or Magnetic?

METAR wind direction is referenced to true north. Wind direction provided by ATC for runway operations is generally magnetic. Do not casually combine the two references in crosswind calculations.

Is Scattered Cloud Cover a Ceiling?

No. The usual ceiling definition is based on the lowest broken or overcast layer, or vertical visibility into an obscuration. Scattered clouds can still affect a flight and should not be dismissed.

Can I Use a TAF as My Entire Weather Briefing?

No. A TAF focuses on an airport and forecast period. It does not fully describe en route turbulence, icing, convective hazards, terrain-related weather, or every condition that could affect a flight.

What Should I Do When a Code Is Unfamiliar?

Look it up in the decoding key in AIM 7-1-28. Guessing at an unfamiliar weather code can turn a meaningful warning into a false sense of confidence.

A Practical Preflight Reading Routine

Start with the departure and destination METARs, checking timestamps. Identify wind, visibility, ceiling, weather phenomena, and trends. Then read the TAFs as timelines covering the actual planned departure and arrival times—not merely the current hour. Compare forecasts with the latest observations. Finally, integrate the airport reports with the broader weather picture: graphical forecasts, radar and satellite products, advisories, PIREPs, winds, and other briefing information relevant to the route and altitude.

If something looks inconsistent, investigate rather than choosing the most optimistic source. If a report shows conditions beyond your comfort or aircraft capability, remember that the point of understanding weather is to make better decisions, including delaying or canceling a flight.

The most important skill is not speed-decoding every abbreviation. It is being able to say, in plain English: what is happening, what is forecast to change, what uncertainty remains, and how does that affect this flight?

References

• FAA Aeronautical Information Manual, Chapter 7, Section 1 — weather reporting, cloud heights, METAR and TAF formats.
• FAA Aviation Weather Handbook, FAA-H-8083-28B — weather concepts, products, interpretation, and operational considerations.
• NOAA/NWS Aviation Weather Center — current aviation weather products and information.