Weather Guide

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

The METAR — Meteorological Aerodrome Report — is the standard format for surface aviation weather observations worldwide. Every pilot needs to be able to decode a METAR quickly and accurately during preflight planning. This guide walks through every element of a real METAR using plain English, so you can go from a raw string of abbreviations to a complete weather picture in under a minute.

What Is a METAR?

A METAR is an observation of current surface weather conditions at a specific airport, generated either by a human weather observer or an automated station. In the United States, METARs are issued hourly (at 53–58 minutes past the hour) and as special observations (SPECI) when conditions change significantly between scheduled reports. You can find current METARs at aviationweather.gov, through ForeFlight, Garmin Pilot, or any other EFB.

A Real METAR Decoded

Let's decode this example METAR from San Diego International:

METAR KSAN 141553Z 27012KT 10SM FEW025 BKN250 22/14 A2992 RMK AO2 RAE32 SLP132 T02220139

A Southern California morning METAR (8:53 a.m. local) with remarks

METAR — Report Type

The first element identifies the report type. METAR is a routine hourly observation. SPECI is a special observation issued when conditions change significantly — a rapidly dropping ceiling, sudden wind shift, or thunderstorm onset.

KSAN — Station Identifier

The four-letter ICAO airport identifier. In the contiguous United States, identifiers begin with K (Alaska and Hawaii use identifiers beginning with P, such as PANC and PHNL). KSAN is San Diego International (Lindbergh Field). International airports use two-letter country codes — EGLL is London Heathrow, LFPG is Paris Charles de Gaulle.

141553Z — Date and Time

Day of the month followed by time in UTC (Zulu). 14 is the 14th day of the month. 1553Z is 15:53 UTC. Always convert to local time using your time zone offset. In California (PDT, UTC−7), 1553Z is 8:53 AM local time.

27012KT — Wind

Wind direction and speed. 270 is the direction the wind is coming FROM in degrees true. 12KT is the speed in knots. So this is a 12-knot wind from the west. Gusts are reported as G followed by the gust speed — 27012G22KT means winds from 270 at 12 knots gusting to 22. Variable winds below 6 knots are reported as VRB. Calm winds are 00000KT.

Training Note

Wind direction in a METAR is reported in degrees true, not magnetic. When flying, you use magnetic headings — so you need to apply local magnetic variation when comparing METAR winds to runway headings. ATC gives winds in magnetic when issuing clearances, which is why the tower may report a slightly different direction than the METAR.

10SM — Visibility

Prevailing visibility in statute miles. 10SM means 10 statute miles — the maximum reportable visibility in US METARs. In TAFs (not METARs), P6SM means "plus 6 statute miles" — visibility forecast to be greater than 6 SM. Low visibility is reported as a fraction: 1/4SM, 1/2SM, etc. VFR minimums for most airspace require at least 3 statute miles visibility.

FEW025 BKN250 — Sky Condition

Cloud layers are reported from lowest to highest. Each layer shows coverage and height above ground level (AGL) in hundreds of feet:

So FEW025 means a few clouds at 2,500 feet AGL. BKN250 means broken clouds at 25,000 feet AGL. The ceiling is the lowest broken or overcast layer — here 25,000 feet, which is perfectly flyable VFR. CB (cumulonimbus) or TCU (towering cumulus) may be appended: FEW030CB means a few cumulonimbus at 3,000 feet — always a significant weather indicator.

22/14 — Temperature and Dewpoint

Temperature and dewpoint in degrees Celsius, separated by a slash. 22 is the temperature (22°C / 72°F). 14 is the dewpoint (14°C / 57°F). Temperatures below zero use M for minus — M05/M10 is −5°C temperature, −10°C dewpoint.

The temperature/dewpoint spread is important for VFR pilots: a small spread means higher relative humidity and fog or low clouds are more likely. A spread of 3°C or less is a warning sign for possible fog formation, especially overnight or in the morning.

A2992 — Altimeter Setting

The current altimeter setting in inches of mercury (inHg). A2992 means set your altimeter to 29.92 inHg. International METARs use Q followed by QNH in hectopascals — Q1013 is 1013 hPa (approximately standard pressure). Always set your altimeter to the current setting before departure and update it throughout your flight.

The Remarks Section (RMK)

Everything after RMK is additional information not captured in the coded body. The remarks section contains some of the most operationally useful information in the METAR.

AO2 — Station Type

AO1 means automated station without precipitation discriminator. AO2 means automated station with precipitation discriminator — it can distinguish between rain, snow, and freezing precipitation. Most modern AWOS and ASOS stations are AO2.

SLP132 — Sea Level Pressure

Sea level pressure in hectopascals. To decode: if the first digit after SLP is 9, prepend 9. If it's 0 or 1, prepend 10. SLP132 → 1013.2 hPa. SLP982 → 998.2 hPa. Useful for weather analysis but not operationally critical for most GA flights.

RAE32 — Precipitation Begin/End Times

This is one of the most misunderstood remark codes. RAE32 means rain ended at 32 minutes past the hour — so although no precipitation is falling at observation time, it was raining about 20 minutes earlier. The pattern is always weather type, then B (began) or E (ended), then the time in minutes past the hour (or four digits, HHMM, if it happened in the previous hour). Several events can be strung together: RAB05E30 means rain began at :05 and ended at :30, and TSB32RAB32 means a thunderstorm and rain both began at :32.

Other common remarks you'll see:
PRESRR — Pressure rising rapidly (0.06 inHg or more per hour)
PRESFR — Pressure falling rapidly
WSHFT HHMM — Wind shift occurred at the stated time
T02220139 — Precise temperature and dewpoint in tenths: 0222 = +22.2°C, 0139 = +13.9°C (a leading 1 instead of 0 means below zero)
RVRNO — Runway Visual Range not available
PWINO
— Precipitation identifier not available

Practical Tip

When reading a METAR, focus on four things first, in order: ceiling, visibility, wind, and altimeter. Those four elements determine VFR/IFR conditions and affect your approach and landing. Once you have those, then dig into temperature/dewpoint spread and remarks for the full picture.

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