How to Read a METAR

Every pilot checks the weather before flying. The METAR is your most important tool for that job. Learning how to read a METAR turns a confusing string of letters and numbers into a clear picture of airport conditions. This guide walks you through each element so you can decode any METAR with confidence.

What Is a METAR and Why It Matters#

A METAR (Meteorological Aerodrome Report) is an official weather observation from an airport. Airports worldwide issue these reports every hour. During rapidly changing conditions, airports publish special updates called SPECIs.

METARs give you critical information for flight planning:

• Visibility at the airport
• Wind speed, direction, and gusts
• Temperature and dewpoint
• Cloud coverage and ceiling height
• Current weather phenomena (rain, fog, snow)
• Altimeter setting for your pressure instruments

The format is standardized internationally. A pilot in Chicago reads a METAR the same way as a pilot in London. This consistency lets pilots, dispatchers, and ATC communicate weather efficiently.

One key distinction: a METAR reports current conditions only. It's a snapshot, not a prediction. For forecasted weather, you need a TAF (Terminal Aerodrome Forecast). For a broader look at aviation weather concepts, the guide Aviation Weather Explained covers forecasts, hazards, and go/no-go decisions in depth.

The Basic Structure of a METAR Report#

Every METAR follows the same order. Once you learn this sequence, decoding becomes almost automatic.

The elements appear in this fixed pattern:

1. Report type (METAR or SPECI)
2. Station identifier
3. Date and time (UTC)
4. Wind
5. Visibility
6. Weather phenomena
7. Sky condition (clouds)
8. Temperature and dewpoint
9. Altimeter setting
10. Remarks

Each element is separated by a space. The report reads left to right, moving from "where and when" to "what's happening." This METAR format explained step by step is how professional pilots scan weather reports quickly.

How to Read METAR: Identifier, Time, and Wind Data#

Let's start with the first three groups in any METAR.

Station Identifier#

The station identifier is a four-letter ICAO code. In the US, these start with K (KJFK for New York JFK, KORD for Chicago O'Hare). Canadian stations start with C, European stations often start with E or L.

Date and Time#

Time appears as a six-digit group followed by Z. The format is DDHHMM Z (day, hour, minute in UTC/Zulu time). For example, 121851Z means the 12th day of the month at 18:51 UTC. Always convert to your local time zone for planning.

Wind Group#

Wind is reported as a five-digit group (or more with gusts). The first three digits show direction in degrees true north. The next two show speed in knots.

• 18010KT = wind from 180° at 10 knots
• 18010G20KT = wind from 180° at 10, gusting to 20 knots
• 00000KT = calm wind
• VRB03KT = variable direction at 3 knots

Strong, gusty winds may signal potential crosswind challenges. The guide Crosswind Explained covers how to calculate crosswind components for your runway.

Understanding Visibility and Weather Phenomena#

Visibility#

US airports report visibility in statute miles. A report of 10SM means 10 statute miles. International airports often report in meters, with 9999 meaning visibility of 10 km or greater.

P6SM means "greater than 6 statute miles." The P stands for "plus," not "prevailing." VFR flight in Class E airspace requires at least 3 SM visibility and a 1,000-foot ceiling.

Weather Codes#

Between visibility and clouds, you may see weather codes. These tell you what's falling from the sky or reducing visibility.

Common METAR abbreviations include:

• RA = rain
• SN = snow
• BR = mist
• FG = fog
• TS = thunderstorm
• SH = showers
• HZ = haze
• DZ = drizzle

Intensity is shown by a prefix. A minus sign means light, no prefix means moderate, and a plus sign means heavy. So -RA is light rain, while +SN is heavy snow.

VC (vicinity) means the weather is nearby but not at the airport. RE (recent) means conditions occurred in the past hour but have stopped.

Reading Temperature, Dewpoint, and Pressure#

Temperature and Dewpoint#

Temperature and dewpoint appear as a pair separated by a slash. For example, 23/14 means 23°C temperature and 14°C dewpoint.

The letter M before a number means "minus" (below zero). M05/M08 means -5°C temperature, -8°C dewpoint. Beginners often confuse M with "missing." In temperature groups, M always means minus.

The spread between temperature and dewpoint matters. A narrow spread (3°C or less) warns you that fog or low clouds may form. This also affects density altitude, which the guide Density Altitude Explained covers in detail.

Altimeter Setting#

In the US, the altimeter setting starts with A followed by four digits. A3012 means 30.12 inches of mercury (inHg). International stations use Q followed by hectopascals (Q1013 = 1013 hPa).

Set this value in your altimeter before departure. An incorrect altimeter setting means your altitude readout is wrong, a dangerous situation near terrain or in busy airspace.

Common METAR Abbreviations and Modifiers#

Cloud coverage uses specific terms based on sky coverage in eighths (oktas):

• SKC = sky clear (no clouds)
• FEW = few (1/8 to 2/8 coverage)
• SCT = scattered (3/8 to 4/8)
• BKN = broken (5/8 to 7/8)
• OVC = overcast (8/8, full coverage)

Cloud height is reported in hundreds of feet above ground level (AGL). BKN025 means broken clouds at 2,500 feet AGL. The ceiling is the lowest layer reported as BKN or OVC.

Some international METARs use CAVOK (Ceiling and Visibility OK). This means visibility is at least 10 km, no significant weather, and no clouds below 5,000 feet.

Putting It Together: A Real-World Example#

Here's a complete METAR. Let's decode it piece by piece.

KJFK 121851Z 18010G20KT 10SM -RA BKN025 OVC050 23/14 A3012 RMK AO2

Breaking it down:

• KJFK = New York JFK Airport
• 121851Z = 12th of the month, 18:51 UTC
• 18010G20KT = wind from 180° at 10 knots, gusting to 20
• 10SM = 10 statute miles visibility
• -RA = light rain
• BKN025 = broken clouds at 2,500 feet AGL (this is the ceiling)
• OVC050 = overcast layer at 5,000 feet
• 23/14 = temperature 23°C, dewpoint 14°C
• A3012 = altimeter 30.12 inHg
• RMK AO2 = remarks section, automated station with precipitation sensor

Now think about what this means for your flight. Visibility is great at 10 SM. The ceiling is 2,500 feet, well above VFR minimums. Light rain is present but not heavy. Winds from the south at 10, gusting 20, so check which runway is active and your crosswind limits. The 9°C temperature/dewpoint spread suggests low fog risk for now.

This is aviation METAR interpretation in action. You're not just decoding symbols. You're extracting the information you need for a safe go/no-go decision.

METAR Limitations and When to Use TAFs#

A METAR is a point observation from a single airport at a single moment. It has real limitations.

Weather can change dramatically between hourly reports. A clear METAR doesn't guarantee clear skies 30 minutes later. Approaching fronts can bring rapid changes in ceiling, visibility, and wind. The guide Air Masses & Fronts in Aviation explains how frontal systems create these fast-moving hazards, including wind shear near the surface.

Always pair your METAR with a TAF. The TAF forecasts conditions for the next 24 to 30 hours. Together, METAR and TAF give you a complete weather picture: what's happening now and what to expect at your destination.

Also check SIGMETs and AIRMETs for en route hazards like icing, turbulence, and thunderstorms. A METAR won't tell you about conditions between airports.

Common Myths About Reading METARs#

Myth: A METAR showing clear skies and 10 SM visibility always means VFR flight is safe. METAR reports conditions at one airport. En route weather, terrain clearance, and destination conditions all affect your flight's safety. A clear departure doesn't guarantee a clear route.

Myth: The letter M always means the same thing in a METAR. Context determines meaning. M before temperature (M05) means minus 5°C. In other positions, it can indicate missing data. Always read the position in the report, not just the symbol.

Myth: A temperature/dewpoint spread of 5°C or less guarantees fog. A narrow spread increases fog and low cloud risk, but fog depends on wind, terrain, and air mass stability. Treat it as a warning sign, not a certainty.

Myth: An hour-old METAR is reliable enough to launch. Weather can change significantly in minutes. Always use the most recent METAR available and verify the time stamp before making decisions.

Frequently Asked Questions#

Key Takeaways#

• A METAR is an hourly weather observation from a specific airport.
• METARs follow a fixed order: identifier, time, wind, visibility, weather, clouds, temp/dewpoint, pressure.
• Station identifiers use four-letter ICAO codes (US stations start with K).
• All METAR times are in UTC (Zulu). Always verify the time stamp.
• Wind is reported in degrees true and knots. Look for G to spot gusts.
• US visibility uses statute miles. International reports may use meters.
• M before temperature means minus (below zero Celsius), not "missing."
• The ceiling is the lowest BKN or OVC cloud layer, reported in hundreds of feet AGL.
• Narrow temperature/dewpoint spread warns of possible fog or low clouds.
• Always pair your METAR with a TAF for a complete weather picture.

Sources & References#

• FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25B), Chapter 13: Aviation Weather Services. Comprehensive guide to reading METARs, TAFs, and other weather products. https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak
• FAA Advisory Circular AC 00-45H: Aviation Weather Services. Official reference for METAR code structure, decoding examples, and weather observation standards. https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1030235
• ICAO Annex 3: Meteorological Service for International Air Navigation. International standard governing METAR format and weather reporting procedures used worldwide.
• National Weather Service Aviation Weather Center. Real-time METARs, TAFs, and advisories with decoding tools. https://aviationweather.gov