METAR&TAFObservation & Forecast · Decoder
Reference · ICAO Annex 3FMH-1 · FAA AC 00-45

METAR explained

A field-by-field reference for the routine surface aviation weather report.

A METAR (Meteorological Aerodrome Report) is the standard hourly observation issued at airports worldwide. The format is defined by ICAO Annex 3 with US conventions in the Federal Meteorological Handbook No. 1 (FMH-1). A METAR packs current weather conditions into a compact one-line code so a pilot, dispatcher, or briefer can read it anywhere with a teletype, voice radio, or text channel.

Here's a typical example. Each token below maps to a specific field.

METAR KLAX 081853Z 27015G22KT 10SM FEW040 BKN100 22/14 A2992 RMK AO2 SLP130

Fields, in order

  1. 01
    METARReport type. SPECI appears on special (off-cycle) reports issued when conditions change significantly between routine hours.
  2. 02
    KLAXICAO station identifier. US stations almost always begin with K; Alaska uses PA, Hawaii PH.
  3. 03
    081853ZDay-of-month and Zulu (UTC) time. The Z suffix means UTC. Here: the 8th of the month, 18:53 UTC.
  4. 04
    AUTO / COROptional flags. AUTO indicates an automated observation; COR is a corrected report.
  5. 05
    27015G22KTWind. Direction (true, in degrees), speed, gust. Here: from 270° at 15 knots gusting 22. VRB replaces direction when wind is variable.
  6. 06
    10SMVisibility in statute miles. Prefixes: P = greater than (P6SM = "more than 6"), M = less than (M1/4SM = "less than ¼"). International stations may report meters (e.g. 9999).
  7. 07
    FEW040 BKN100Sky condition, in layers from lowest to highest. Coverage codes: FEW (1–2 oktas), SCT (3–4), BKN (5–7), OVC (8). Followed by height in hundreds of feet AGL. BKN100 = broken cloud at 10,000 ft. Suffix CB or TCU denotes cumulonimbus or towering cumulus.
  8. 08
    22/14Temperature and dewpoint in Celsius. M prefix means below zero (M02/M05 = -2°C / -5°C).
  9. 09
    A2992Altimeter setting in inches of mercury × 100. Decoded: 29.92 inHg. International stations use Q (hPa, e.g. Q1013).
  10. 10
    RMKBeginning of the remarks block. Contains automation flags (AO1/AO2), sea-level pressure (SLP130), 6-hour temperature extremes, precipitation accumulation, and other supplementary data not part of the core report.

Present weather codes

When precipitation, obscuration, or other significant weather is observed, a code appears between visibility and sky condition. Codes combine an optional intensity (- light, + heavy, VC in vicinity), descriptor, and phenomenon — e.g. +TSRA = heavy thunderstorm with rain, -DZ = light drizzle, BR = mist.

The full table is on the code reference page →

A few worth knowing

  • CAVOK Ceiling and visibility OK. International shortcut, rare in US METARs.
  • NSC No significant clouds (no clouds below 5,000 ft AGL or below the highest minimum sector altitude).
  • VV002 Vertical visibility into an obscuration; sky is not seen but visibility upward is 200 ft.
  • R09L/2000FT Runway visual range. Runway 9 Left, 2,000 ft. The dedicated decoder will note these but not interpret further.

Source For the canonical authority, see aviationweather.gov and FAA Advisory Circular AC 00-45 (Aviation Weather Services). This page is informational only.