METAR Decoder
A METAR (Meteorological Aerodrome Report) is the standard format for reporting current weather conditions at airports worldwide. METARs are issued hourly (or more frequently when conditions change significantly as SPECIs) and contain critical information including wind, visibility, cloud cover, temperature, dewpoint, and altimeter setting.
Understanding METARs is an essential skill for all pilots. Each METAR follows a standardized format defined by ICAO Annex 3 and WMO Publication 306, making them readable by pilots worldwide regardless of language. However, the coded format can be challenging for students and non-pilots to interpret.
Our free METAR decoder translates raw METAR strings into plain English, highlighting key elements like flight category, wind conditions, and weather phenomena. It is provided by METARDecoder.app — a free tool from the same team behind FlightCalculators.com.
Open METAR DecoderMETAR decoding is provided by METARDecoder.app — a free tool from the same team.
How to Read a METAR
A METAR is read left to right in a fixed order, and once you know the sequence the code becomes predictable. A typical report such as KJFK 121651Z 18012G20KT 10SM FEW050 SCT250 28/19 A2992 breaks into distinct fields: the station identifier, the day-and-time of observation in UTC (Zulu), the wind, the visibility, the sky condition, the temperature and dewpoint, and the altimeter setting. Optional groups for present weather (such as -RA for light rain or BR for mist) and remarks (RMK) may follow.
| Group | Example | Meaning |
|---|---|---|
| Station | KJFK | ICAO airport identifier |
| Time | 121651Z | 12th day, 1651 UTC |
| Wind | 18012G20KT | From 180° at 12 kt, gusting 20 kt |
| Visibility | 10SM | 10 statute miles |
| Sky | FEW050 SCT250 | Few at 5,000 ft, scattered at 25,000 ft |
| Temp/Dew | 28/19 | 28°C temperature, 19°C dewpoint |
| Altimeter | A2992 | 29.92 inHg |
Cloud coverage codes describe how much of the sky is obscured in eighths (oktas): SKC/CLR (clear), FEW (1–2 oktas), SCT (scattered, 3–4 oktas), BKN (broken, 5–7 oktas), and OVC (overcast, 8 oktas). A “ceiling” is the lowest BKN or OVC layer, and it is that ceiling—together with visibility—that determines the flight category. The heights are reported in hundreds of feet above ground level, so BKN050 means a broken ceiling at 5,000 ft AGL. This decoding follows the format defined in FAA Advisory Circular 00-45 and ICAO Annex 3.
Related Tools
This METAR decoder is an educational aid. Always obtain an official weather briefing and confirm raw METAR/TAF data from an authoritative source before flight. Read our full Safety Disclaimer.
Decoding METARs in Depth
A METAR is the standard coded hourly observation of surface weather at an airport, and learning to read it fluently is a core skill for every pilot. Behind its dense string of abbreviations lies everything you need for a departure or arrival decision: wind, visibility, cloud layers, temperature and dewpoint, altimeter setting, and significant weather. This tool expands the code into plain language so you can confirm your own reading and build the habit of decoding it directly.
The format is standardized worldwide, which means once you learn the structure you can read an observation from almost any airport. The value of understanding the raw code, rather than relying only on a translated summary, is that the METAR often carries subtle detail — a gust spread, a remark, a rapidly changing element — that a plain-language paraphrase can flatten or omit.
Step-by-Step: How the Calculation Works
A METAR follows a fixed order: station identifier, day-and-time in UTC, sometimes AUTO or a wind-variability note, wind as direction and speed with any gusts, visibility, present weather, cloud layers with their coverage and height, temperature and dewpoint in Celsius, the altimeter setting, and finally remarks. Reading in this order lets you locate any element quickly without parsing the whole string.
The calculator parses each group and labels it: it converts the UTC time, expands wind and gust notation, translates weather abbreviations such as -RA or BR, and gives cloud coverage and bases in feet above the airport. Comparing the decoded output against the raw code trains you to recognize each group, so that over time you read the METAR directly and use the decoder only to confirm the tricky parts.
More Worked Examples
Example 1 — A routine observation
METAR KxxX 121853Z 27012KT 10SM FEW050 24/09 A3002 decodes as: observed at 1853 UTC on the 12th, wind from 270° at 12 knots, visibility 10 statute miles, few clouds at 5,000 ft, temperature 24°C and dewpoint 9°C, altimeter 30.02 inHg — solidly VFR conditions.
Example 2 — Gusts and weather
A group like 18015G25KT 3SM -RA BKN012 shows wind from 180° at 15 knots gusting 25, visibility 3 statute miles in light rain, and a broken ceiling at 1,200 ft. The gust spread and the 1,200-ft ceiling immediately flag a demanding crosswind and Marginal-to-IFR conditions worth close attention.
Pilot Decision-Making Context
Fluent METAR reading feeds directly into go/no-go decisions. The wind group reveals the crosswind you will face; the visibility and cloud groups set the flight category; the altimeter feeds your density-altitude and altitude planning; and the temperature-dewpoint spread hints at fog or low cloud potential. Reading these together builds a complete picture faster than any single translated line.
The remarks section rewards the pilot who does not stop at the main body. Notes on pressure trends, peak winds, or the beginning and ending of precipitation can change a decision, and they are exactly the details a quick summary tends to drop. Treating the full METAR as the authoritative source keeps you closer to the real conditions.
More Questions Answered
What time zone does a METAR use?
Always UTC, indicated by the Z after the day-and-time group. Convert to local time for planning, but remember all aviation weather and flight plans reference UTC.
What does a group like 18015G25KT mean?
Wind from 180 degrees true at 15 knots, gusting to 25 knots. The G separates the sustained speed from the gust value.
Are cloud heights in a METAR above sea level or the airport?
Cloud bases in a METAR are reported in feet above ground level at the reporting station, not above sea level.
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