How to Read a METAR — METAR Decoder Guide for Pilots
A METAR (Meteorological Aerodrome Report) is a standardized weather observation issued by airports worldwide. Pilots, dispatchers, and aviation weather briefers use METARs to assess current conditions before and during flight. This guide breaks down every part of a METAR so you can decode any report in seconds.
METAR Example — Decoded Step by Step
KJFK 091756Z 31012G20KT 10SM FEW250 M02/M17 A3042 RMK AO2 SLP314KJFKICAO identifier for John F. Kennedy International Airport
091756ZIssued on the 9th of the month at 17:56 UTC (Zulu time)
31012G20KTWind from 310 degrees at 12 knots, gusting to 20 knots
10SM10 statute miles visibility (the maximum reported)
FEW250Few clouds at 25,000 feet AGL (1-2 oktas of sky coverage)
M02/M17Temperature minus 2 degrees C, dewpoint minus 17 degrees C (M = minus)
A3042Altimeter setting 30.42 inches of mercury
RMK AO2 SLP314Automated station with precipitation sensor, sea level pressure 1031.4 hPa
METAR Format — The Standard Order
Every METAR follows the same order. Once you learn the pattern, you can read any METAR report at a glance:
- Station Identifier — 4-letter ICAO code (e.g. KJFK, EGLL, RJTT)
- Date/Time — Day of month + time in Zulu (UTC), always ending in Z
- Wind — Direction (true), speed, gusts in knots (e.g. 27015G25KT)
- Visibility — In statute miles (SM) in the US, meters elsewhere
- Weather Phenomena — Rain, snow, fog, etc. using standard codes
- Cloud Layers — Coverage + height in hundreds of feet AGL
- Temperature/Dewpoint — In whole degrees Celsius. M = minus (below zero)
- Altimeter Setting — A followed by 4 digits (e.g. A2992 = 29.92 inHg)
- Remarks (RMK) — Additional info: station type, sea level pressure, etc.
Flight Categories — VFR, MVFR, IFR, LIFR
Flight categories are determined by the lowest ceiling and prevailing visibility reported in a METAR. The most restrictive value determines the category:
Clear conditions suitable for visual flight.
Marginal conditions. Extra caution required.
Instrument flight rules required. IFR clearance needed.
Low IFR. Most restrictive conditions.
See flight categories live on the Hangar METAR Map — 70,000+ airports color-coded in real time.
Cloud Cover Abbreviations
Cloud layers in a METAR are reported as a coverage code followed by the height in hundreds of feet above ground level (AGL). Only BKN and OVC constitute a ceiling.
| Code | Meaning | Oktas | Notes |
|---|---|---|---|
SKC/CLR | Clear | 0 | No clouds reported. SKC is used by manual stations, CLR by automated. |
FEW | Few | 1-2 | Trace cloud coverage. Does not constitute a ceiling. |
SCT | Scattered | 3-4 | Partial cloud coverage. Does not constitute a ceiling. |
BKN | Broken | 5-7 | Mostly cloudy. This IS a ceiling layer for flight category. |
OVC | Overcast | 8 | Complete cloud coverage. Full ceiling. |
Weather Phenomena Codes
Weather phenomena appear between visibility and cloud layers in a METAR. Intensity prefixes (+ or -) and descriptors (like FZ for freezing) combine with the base codes:
| Code | Meaning |
|---|---|
RA | Rain |
SN | Snow |
DZ | Drizzle |
FG | Fog (visibility below 5/8 SM) |
BR | Mist (visibility 5/8 to 6 SM) |
HZ | Haze |
TS | Thunderstorm |
SH | Showers |
GR | Hail |
FZ | Freezing (prefix: FZRA = freezing rain) |
+ | Heavy intensity (prefix: +RA = heavy rain) |
- | Light intensity (prefix: -SN = light snow) |
METAR vs TAF — What's the Difference?
Pilots often use METARs and TAFs together, but they serve different purposes:
METAR
- Current weather observation
- Issued hourly (or when conditions change)
- Reports what conditions are right now
- Valid for approximately 60 minutes
TAF
- Weather forecast
- Issued every 6 hours
- Covers the next 24-30 hours
- Includes expected changes over time
Frequently Asked Questions
What does METAR stand for?
METAR stands for Meteorological Aerodrome Report (or Meteorological Terminal Air Report). It is a standardized format for reporting weather observations at airports and weather stations worldwide.
How often is a METAR updated?
Routine METARs are issued once per hour, typically around 55 minutes past the hour. Special METARs (SPECIs) are issued whenever conditions change significantly, such as a sudden drop in visibility or a wind shift.
Are METAR winds true or magnetic?
METAR wind directions are always reported relative to true north. This is different from ATIS and tower communications, which report winds relative to magnetic north. When comparing METAR winds to runway headings, remember to account for magnetic variation.
Are METAR ceilings AGL or MSL?
METAR cloud heights are reported in feet above ground level (AGL), not above mean sea level (MSL). This is important for determining flight categories and planning approaches.
How long is a METAR valid for?
A METAR is an observation of current conditions and is valid at the time of issuance. As a general rule, pilots treat METARs as current for up to 60 minutes after issuance. After that, a new observation should be expected. Weather can change rapidly, so always check for the most recent METAR before flight.
What is the difference between METAR and TAF?
A METAR is a current weather observation — what conditions are right now. A TAF (Terminal Aerodrome Forecast) is a forecast covering the next 24-30 hours. Pilots use both: METARs for current conditions and TAFs for planning ahead. TAFs include expected changes in wind, visibility, and clouds over time.
What does AO2 mean in a METAR?
AO2 in a METAR indicates that the station is an automated observation station with a precipitation discriminator — meaning it can distinguish between different types of precipitation (rain, snow, etc.). AO1 indicates an automated station without this capability.
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