How to Read a METAR: A Pilot's Complete Guide

You're in the flight school lobby with 30 minutes until your lesson. Your instructor texts: "Check the METAR for KBOS and let me know what you think." You pull up the weather and stare at this:

If that looks like a random string of letters and numbers, you're not alone — every pilot has been there. But here's the thing: every single piece of that string follows a fixed, learnable format. Once you understand the structure, you can decode any METAR in seconds.

This guide walks through every field, one at a time. By the end you'll be able to read the full picture from raw text — wind, visibility, cloud ceiling, weather phenomena, altimeter setting, and the remarks section that most pilots skip (but shouldn't).

What Is a METAR?

A METAR (Meteorological Aerodrome Report) is a standardized, text-based report of current surface weather conditions at an airport. It is issued at regular intervals — typically at the top of every hour, and at 20 and 50 minutes past the hour at larger stations — by automated sensor systems called ASOS (Automated Surface Observing System) or AWOS (Automated Weather Observing System), and occasionally by human weather observers.

METARs are an ICAO (International Civil Aviation Organization) standard, which means the format is the same whether you're reading a report from Boston, London, or Tokyo. The primary differences between US and international METARs are the visibility unit (statute miles vs. meters) and the altimeter format (A for inches of mercury vs. Q for hectopascals).

You'll find METARs on aviationweather.gov, in ForeFlight, Garmin Pilot, and any aviation weather app. The FAA also incorporates METARs into the standard weather briefing you receive before every flight.

The Anatomy of a METAR — Field by Field

Every METAR follows the same field order. We'll use this example throughout the section — a marginal IFR day at Boston Logan:

Here's the complete field-order reference, then we'll dig into each one:

Field	Format Pattern	Example	Plain English
Station ID	KXXX	KBOS	Boston Logan Intl
Date & Time	DDHHMMZ	171553Z	17th day, 15:53 UTC
Wind	DDDSS(G SS)KT	24015G22KT	From 240° at 15 kts, gusting 22
Visibility	N SM	3SM	3 statute miles
Weather Phenomena	(-)PPPP	-RA BR	Light rain and mist
Sky Condition	CCCHHH	OVC010	Overcast at 1,000 ft AGL
Temperature / Dewpoint	TT/DD	08/06	8°C temp, 6°C dewpoint
Altimeter	ANNNN	A2988	29.88 inHg
Remarks	RMK ...	RMK AO2 SLP116	Auto station; SLP 1011.6 hPa

Station Identifier

The first field is the four-character ICAO station identifier. In the continental US, all identifiers start with K, followed by the three-letter FAA airport code. So Boston Logan (BOS) becomes KBOS, O'Hare (ORD) becomes KORD, and Denver International (DEN) becomes KDEN.

Exceptions: Alaskan stations typically start with PA, Hawaiian stations with PH, and Canadian stations with C. This matters when reading cross-border METARs.

Date and Time (Zulu)

The date/time group follows the format DDHHMMZ — day of month, hour, minute, and the letter Z for Zulu (UTC). In our example, 171553Z means the 17th day of the month at 15:53 UTC.

Aviation uses UTC (Coordinated Universal Time) universally so that pilots, controllers, and dispatchers across time zones all reference the same clock. There is no daylight saving adjustment in Zulu time.

Wind

Wind is reported as DDDSSKT — a three-digit direction (in degrees true), two-digit speed in knots, and the unit KT. When gusts are present, a G and the gust speed are inserted: DDDSSGSSGKT.

Wind direction is always the direction the wind is coming from, not blowing toward. 24015G22KT means wind from 240° (southwest) at 15 knots, gusting to 22 knots. Special cases: VRB06KT means variable direction at 6 knots (common in light, unstable air); 00000KT means calm.

Visibility

In US METARs, visibility is reported in statute miles followed by SM. A reading of 10SM is the maximum reported value and simply means visibility is at least 10 statute miles — "unlimited" for practical purposes. You'll also see:

• 3SM — 3 statute miles (marginal VFR to IFR territory)
• 1 1/2SM — one and a half statute miles (IFR)
• 3/4SM — three-quarter mile (IFR)
• 1/4SM — quarter-mile (likely LIFR)
• P6SM — greater than 6 statute miles (used in TAFs)

When visibility drops below 6,000 feet on a specific runway, you may also see RVR (Runway Visual Range) appended, reported in hundreds of feet. For example, R04R/2400FT means Runway 4 Right has an RVR of 2,400 feet.

International METARs report visibility in meters (e.g., 9999 = 10 km or more, 0600 = 600 meters). This is the most common source of confusion when reading non-US reports.

Weather Phenomena (Present Weather)

Present weather follows the format: [intensity] [descriptor] [precipitation / obscuration]. Not all components are always present.

Intensity: A minus (-) means light, no prefix means moderate, a plus (+) means heavy. VC means in the vicinity (within 5–10 miles but not at the station).

In our example, -RA BR = light rain (-RA) and mist (BR). Two separate weather phenomena are listed side by side.

Sky Condition

Sky condition reports cloud coverage and height above ground level in the format CCCHHH — a three-letter coverage code followed by height in hundreds of feet AGL.

OVC010 means overcast (OVC) at 1,000 feet AGL (10 × 100 ft). A METAR may contain up to three sky condition groups, listed from lowest to highest: for example, FEW020 SCT060 BKN120.

The ceiling is the lowest broken or overcast layer. FEW and SCT layers are never a ceiling. This distinction matters enormously: a pilot filing VFR cannot legally fly if the ceiling is below 1,000 feet (within controlled airspace), even if there are scattered clouds above.

VV (vertical visibility) is reported instead of a standard sky condition when the sky is completely obscured — by fog, smoke, or blowing snow. VV008 means vertical visibility into the obscuration is 800 feet.

Temperature and Dewpoint

Temperature and dewpoint are both reported in degrees Celsius, separated by a slash: TT/DD. Negative values are prefixed with M (minus): M03/M07 = −3°C temp, −7°C dewpoint.

In our example, 08/06 means 8°C temperature and 6°C dewpoint — a spread of only 2 degrees. A tight spread signals high relative humidity: when the spread drops to 2°C or less, fog formation or deteriorating visibility becomes likely, especially at night or during periods of light wind. A pilot watching a temp/dew spread close during an evening flight should plan accordingly.

Altimeter Setting

The altimeter setting field tells you what pressure to set in your Kollsman window. In US METARs, it starts with A followed by four digits representing inches of mercury (inHg) to the hundredths: A2988 = 29.88 inHg.

Standard sea-level pressure is 29.92 inHg. When the altimeter is above standard, pressure is higher than average; when below, pressure is lower. International METARs use Q followed by hectopascals (millibars): Q1013 = 1013 hPa ≈ 29.92 inHg.

Remarks (RMK)

The remarks section begins with RMK and contains supplemental data not captured in the standard fields. Many pilots ignore remarks — but they often contain critical information.

Common remarks and what they mean:

• AO1 — Automated station without a precipitation type discriminator (can't distinguish rain vs. snow)
• AO2 — Automated station with a precipitation discriminator (the reliable one)
• SLP116 — Sea Level Pressure 1011.6 hPa (prefix 9 or 10 to first two digits, add decimal before last digit)
• P0012 — Precipitation accumulation of 0.12 inches in the past hour
• T00830061 — Precise temperature 8.3°C, precise dewpoint 6.1°C (T-group)
• PRESRR — Pressure rising rapidly (>0.06 inHg in past hour) — improving conditions likely
• PRESFR — Pressure falling rapidly — deteriorating conditions likely
• PK WND 28045/1530 — Peak wind of 45 knots from 280° at 15:30 UTC
• WSHFT 1510 — Wind shift at 15:10 UTC — frontal passage indication

Flight Categories: VFR, MVFR, IFR, LIFR

Every METAR can be summarized with one of four flight category labels based on its ceiling and visibility. These categories are standardized by the FAA and used by every aviation weather product in the US.

The logic is an OR, not an AND: if either ceiling or visibility meets the threshold for a lower category, that lower category applies. A clear sky with 1/2-mile visibility in fog is still IFR. A 500-foot ceiling with 10-mile visibility is still IFR.

For our Boston example (OVC010 3SM): ceiling is 1,000 feet (IFR: 500–999 ft qualifies, but 1,000 ft is in the MVFR range) and visibility is 3SM (MVFR: 3–5SM). Ceiling is 1,000 ft AGL which is right at the MVFR/IFR boundary — technically MVFR ceiling, but visibility of exactly 3SM is also MVFR. The station would be classified MVFR.

When you open a weather app and see a colored dot next to an airport identifier, it's derived from exactly this logic — ceiling and visibility thresholds applied automatically. Understanding the underlying rules means you can always sanity-check what you see on screen.

Special METARs (SPECI)

A SPECI (Special METAR) is an out-of-cycle observation issued whenever conditions change rapidly enough to warrant immediate reporting. It replaces the word METAR at the start of the report.

When you see SPECI in your weather briefing, treat it as a yellow flag: conditions changed fast enough that the system couldn't wait for the next scheduled observation. That's always worth a second look at the updated report.

Worked Example: Decoding a Complete METAR

Let's put it all together with a more challenging real-world METAR — Denver International on a winter morning:

Raw Field	Decoded
KDEN	Denver International Airport (Colorado)
171956Z	17th, 19:56 UTC → 12:56 PM Mountain Standard Time
32008KT	Wind from 320° (NW) at 8 knots, no gusts
1 1/4SM	Visibility 1.25 statute miles — IFR
-SN BR	Light snow and mist
OVC005	Overcast ceiling at 500 feet AGL — borderline LIFR
M02/M04	Temperature −2°C, dewpoint −4°C (2° spread — conditions stable for now)
A3004	Altimeter 30.04 inHg (above standard — typical with cold, dense air)
RMK AO2	Automated station with precipitation discriminator — snow/rain classification reliable
P0000	Trace precipitation in past hour (less than 0.01 inches)
T10171039	Precise temp −1.7°C, precise dewpoint −3.9°C (T-group, 1 = negative)

Bottom line on this METAR: Denver is reporting a 500-foot overcast (borderline IFR/LIFR), 1¼-mile visibility in light snow and mist, light northwest wind, and below-freezing temperatures. This is a solid IFR day with icing potential on approach. No VFR pilot should be launching from DEN right now.

How to Practice Reading METARs

Reading METARs is a skill — and like any skill, it atrophies without practice. A student pilot who reads twenty METARs a day for two weeks will decode them faster and more accurately than one who reads the format guide once and moves on. The gap between knowing the format and fluently reading the report comes entirely from repetition.

Here are three ways to build the habit:

1. Read your home airport's METAR every morning. Pull it up before checking anything else. Try to decode it before looking at a translated version. Takes 90 seconds and builds pattern recognition fast.
2. Check METARs before every flight, even local ones. Even when you know it's VFR, go through each field. You want the motion to be automatic when the conditions actually matter.
3. Use a dedicated practice tool. METAR Master (iOS) pulls live reports from aviationweather.gov, shows you the raw METAR, and lets you decode it mentally before tapping to reveal the full field-by-field breakdown. You mark Got It or Missed It, track your accuracy over time, and advance through pilot ranks from Student Pilot to ATP. It works offline with 200+ bundled reports, costs $1.99 once (no subscription, no ads), and takes about five minutes per session. It's the most efficient way to get the repetitions in.

Frequently Asked Questions

What does METAR stand for?

METAR stands for Meteorological Aerodrome Report. It is an ICAO-standard format for surface weather observations at airports, issued typically once per hour by automated surface observing systems or trained weather observers.

How often are METARs issued?

Standard METARs are issued at the top of every hour (and at 20 and 50 minutes past the hour at Class B airports). A SPECI (special METAR) is issued any time conditions change significantly — such as a drop in ceiling below 1,000 feet, visibility below 3 miles, or an unexpected wind shift.

What is the difference between a METAR and a TAF?

A METAR is an observation — what conditions are right now at a specific airport. A TAF (Terminal Aerodrome Forecast) is a forecast — what conditions are expected to be over the next 24 to 30 hours. TAFs use a similar but extended format that includes change groups (FM, TEMPO, BECMG, PROB) to describe expected transitions.

Where can I find METARs online?

The official source for US METARs is aviationweather.gov (free, no account required). You can also access METARs through ForeFlight, Garmin Pilot, FltPlan Go, and most other aviation weather apps.

What does OVC010 mean?

OVC010 means overcast ceiling at 1,000 feet AGL (above ground level). The three letters (OVC) indicate coverage, and the three digits (010) indicate height in hundreds of feet — so 010 = 1,000 feet. An overcast at 1,000 feet puts the station squarely in IFR conditions.

What does P6SM mean in a METAR?

P6SM means visibility is greater than 6 statute miles. The "P" stands for "plus" (more than). This notation is primarily used in TAFs and in some METAR contexts to indicate unlimited visibility without specifying an exact value above 6 miles.

How do I practice reading METARs?

The most effective approach is daily repetition with real reports. Pull up your home airport's METAR each morning and try to decode it before looking at any translation. For structured practice with instant feedback, METAR Master (iOS) is purpose-built for this — it presents live reports, waits for you to decode, then reveals the full breakdown so you can self-assess.

Keep Reading — Keep Flying

Reading METARs is not a skill you learn once and set aside. The pilots who are fastest and most confident in the weather briefing room are the ones who have read thousands of them — not because they have any special talent, but because the pattern becomes effortless with repetition.

Bookmark this guide as a reference while you're building fluency. And whenever you want to get in some structured reps, METAR Master on the App Store is waiting with a fresh METAR every time you open it.

Clear skies — and keep checking those reports.

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Official reference: FAA Advisory Circular AC 00-45H — Aviation Weather Services