How to Read a METAR and TAF: A Group-by-Group Decoding Guide for FAA Pilots

A METAR is an hourly observation and a TAF is a forecast, and both use the same coded groups in a fixed order: station, time, wind, visibility, weather, sky condition, temperature and dew point, then altimeter setting. In the United States, visibility is in statute miles and the altimeter setting is in inches of mercury.

Checked against: AIM paragraph 7-1-28 and Figures 7-1-22 and 7-1-23, Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR) (AIM dated 2/20/25); FAA-H-8083-28B Aviation Weather Handbook, Chapter 3 (flight categories).

The structure of a METAR: the order never changes

A METAR (Aviation Routine Weather Report) is the standard hourly surface observation. It is built from groups that always appear in the same order, so once you know the order you can read any report quickly. The sequence is the message type, the location, the date and time, the wind, the visibility, runway visual range when reported, the present weather, the sky condition, the temperature and dew point, the altimeter setting, and then remarks.

The FAA key in the Aeronautical Information Manual (paragraph 7-1-28) lays the same groups out side by side for a forecast and a report, which is useful because the TAF borrows most of the METAR vocabulary. The difference is purpose: a METAR says what was observed at the time stamped on it, and a TAF says what is expected during a stated valid period.

When you study, read every report from left to right and name each group out loud before you interpret the whole. Most misreads come from skipping a group, for example taking a gust figure as the steady wind or reading a date group as a time.

Date, time and wind: the first groups you read

The time group is a two-digit day of the month followed by a four-digit time in UTC, written with a Z. In the AIM sample, 091955Z is the 9th at 1955 Zulu. Weather decisions depend on how old the observation is, so always check the time before the conditions.

The wind group is a three-digit direction in degrees true, rounded to the nearest 10, followed by the speed and the unit KT for knots. A gust is added with G and the maximum speed, so 22015G25KT is from 220 degrees at 15 knots gusting to 25. A calm wind is written 00000KT, and VRB means the direction is variable. When the direction varies by 60 degrees or more, a variability group such as 180V260 is appended in a METAR.

Remember that wind in a METAR is true north, not magnetic. Runway headings are magnetic, so compare them carefully when you work out a crosswind component. Wind reported by a control tower or ATIS is given in magnetic, which is one reason the same airport can seem to disagree with itself.

• Date and time: two-digit day, four-digit UTC time, then Z.
• Wind: three-digit direction true, speed, optional G and gust, then KT.
• Calm is 00000KT; VRB is variable; 180V260 is a direction range.

Visibility, runway visual range and present weather

In the United States, prevailing visibility is reported in statute miles and fractions followed by SM, so 3/4SM is three-quarters of a mile and P6SM in a TAF means more than six statute miles. Outside the United States, visibility is usually a four-digit value in meters, so check the unit before you compare it with a minimum.

Runway visual range is reported with R, the runway designator, a slash and a value in feet in the United States. R28L/2600FT is the visual range along runway 28 left. It appears when it is reported, usually at larger airports with low visibility.

Present weather follows. An intensity sign comes first: a minus is light, no sign is moderate and a plus is heavy. Descriptors such as TS for thunderstorm or SH for showers combine with phenomena such as RA for rain or SN for snow, so TSRA is a thunderstorm with rain and +TSRA is the same with heavy rain. VC means the weather is in the vicinity but not at the airport.

Sky condition: cover, height and ceiling

Sky condition groups give the amount of cloud, the base height in hundreds of feet above ground level and, where relevant, the cloud type. The cover codes are SKC or CLR for clear, FEW for more than none up to two eighths, SCT for scattered at three to four eighths, BKN for broken at five to seven eighths and OVC for overcast at eight eighths. OVC010CB is an overcast layer at 1,000 feet with cumulonimbus.

More than one layer may be reported, and an obscured sky uses vertical visibility, written VV followed by a height such as VV004. Because heights are in hundreds of feet above the ground, the group 010 is 1,000 feet, not 10 feet and not 10,000 feet.

The ceiling is the height of the lowest broken or overcast layer, or the vertical visibility into an obscuration. Few and scattered layers do not make a ceiling. This is why a sky of FEW008 SCT020 has no ceiling even though cloud is reported at 800 feet, and why you should read down the layers rather than stopping at the first one.

Temperature, dew point, altimeter setting and remarks

Temperature and dew point are reported in whole degrees Celsius separated by a slash, with M for minus. A report of 18/16 shows a spread of only two degrees, which is the signal to expect fog, low cloud or reduced visibility when the temperature falls further, and a prompt to think about carburetor icing in a piston aircraft.

The altimeter setting begins with A in the United States and is followed by four digits for inches of mercury to hundredths, so A2992 is 29.92 inches. In many other countries the group begins with Q and is in hectopascals, for example Q1013. Set the value in the altimeter window when you are cleared to or approach the airport, and compare it with field elevation on the ground as a check.

Remarks begin with RMK. In the AIM sample, SLP045 gives sea-level pressure of 1004.5 hectopascals and T01820159 gives temperature of 18.2 degrees and dew point of 15.9 degrees Celsius in tenths. Remarks carry operationally important detail such as the thunderstorm location or a pressure trend, so do not skip them.

Reading a TAF: valid period and change groups

A TAF (Terminal Aerodrome Forecast) starts like a METAR: message type, location, issuance time in UTC, and then a valid period written as two date-and-hour pairs. In the AIM sample, 0918/1024 means valid from 1800Z on the 9th until 2400Z on the 10th. The first two digits of each four-digit number are the date and the last two are the hour.

The base forecast gives wind, visibility and sky condition for the start of the period, and change groups then modify it. FM, for from, starts a new set of conditions at a stated day, hour and minute, and the AIM warns that FM100000 is 0000Z on the 10th, not 1000Z. BECMG is a gradual change over the stated period. TEMPO is a temporary fluctuation lasting less than an hour at a time and less than half the period. PROB with 30 or 40 is a probability of conditions in the stated period.

A TAF can also include non-convective low-level wind shear as WS, a three-digit height in hundreds of feet, a slash, and the wind above that height, as in WS010/31022KT. Read the group that applies at the time you will arrive, not simply the first line, and combine the TAF with current METARs, since the TAF is a forecast and the METAR is what is happening now.

Flight categories and how they relate to the VFR minimums

Weather websites color station plots by flight category so a map of METARs can be scanned quickly. The Aviation Weather Handbook defines VFR as a ceiling greater than 3,000 feet and visibility greater than 5 statute miles, MVFR as a ceiling of 1,000 to 3,000 feet or visibility of 3 to 5 miles, IFR as a ceiling of 500 to less than 1,000 feet or visibility of 1 to less than 3 miles, and LIFR below that.

The handbook is explicit that these categories are for situational awareness and are not the basic VFR weather minimums in 14 CFR 91.155. A report in the VFR category does not mean you may fly VFR in every airspace, and a report in MVFR does not by itself make a flight illegal. Use the category to scan, then check the regulation for the airspace and altitude you will actually use.

For the knowledge test, expect questions that give you a METAR or TAF and ask for a single element, such as the wind component, the ceiling or the validity of a change group. Practice decoding the whole report each time, because the question may only ask about one group but the trap is usually in another.

Frequently Asked Questions (FAQ)

Official sources

• FAA: Aeronautical Information Manual, paragraph 7-1-28 Key to TAF and METAR
• FAA: Aviation Weather Handbook (FAA-H-8083-28)
• eCFR: 14 CFR 91.155 Basic VFR weather minimums

Keep studying

• FAA VFR Weather Minimums and Cloud Clearances Guide (14 CFR 91.155) →
• Part 107 weather and operating limits: sources, minimums and performance effects →