METAR Decoder
Paste a METAR or SPECI report and read it line by line: wind, visibility, weather, clouds, temperature, altimeter, flight category and remarks, each with its original code.
Free · runs in your browser · nothing is uploaded
The METAR decoder turns a raw METAR or SPECI weather report into a plain English table. Paste one report or several, and each one is split into rows for the station, observation time, wind, visibility, runway visual range, present weather, clouds, temperature, altimeter, flight category and remarks. Every row shows the original code group beside its meaning, so you can see how the code is built.
The decoder reads the text you paste and does not fetch live weather. Copy the report from an official source such as aviationweather.gov, paste it in, and read the table. If you need a forecast instead of an observation, use the TAF decoder.
How to use the METAR decoder
- Copy a METAR or SPECI from your weather source and paste it into the box. For several reports, put one per line or separate them with an equals sign.
- Read the table. Each row has an Item, the raw Group and the Plain English meaning.
- Check wind, visibility, present weather and clouds first. The flight category row summarises them as VFR, MVFR, IFR or LIFR and states the ceiling.
- Look at the temperature row for Celsius and Fahrenheit and the spread between temperature and dew point, then at the altimeter row for inHg and hPa.
- Read the remarks. A remark the decoder does not recognise is listed as “Not decoded” with its raw text.
- Open the crosswind calculator link under the table to carry the report’s wind into that tool, or the cloud base link to carry the temperature and dew point.
- Use “Copy decoded text” to copy the result into your notes, a briefing sheet or a message.
- Paste another report, or use the Clear button, to start again.
The example buttons load a gusty US report, a UK report in metres and hectopascals, a CAVOK report, fog with runway visual range, a thunderstorm and a snow report from Canada.
What does METAR mean?
A METAR is the aviation routine weather report: a coded observation of the weather at one airport at one time. It is issued on a regular schedule, and a SPECI is a special report that can be issued between routine reports when conditions change. Both use the same code, so the decoder reads either.
How do you read a METAR?
Read the groups from left to right. In KJFK 251851Z 31015G25KT 10SM FEW050 SCT250 18/09 A3012 the station is KJFK, 251851Z is day 25 at 18:51 UTC, and 31015G25KT is wind from 310 degrees true at 15 knots gusting to 25. Visibility is 10 statute miles (about 16.1 km). Few clouds are at 5,000 ft and scattered clouds at 25,000 ft, above the ground.
The temperature is 18 C (64 F) and the dew point 9 C (48 F), a spread of 9 C. A3012 is an altimeter setting of 30.12 inHg, or 1,020 hPa. With no broken or overcast layer the report has no ceiling, so the category is VFR. After RMK come remarks such as AO2, an automated station with a precipitation discriminator, and SLP201, a sea level pressure of 1020.1 hPa.
Which flight category thresholds are used?
The category is set by the worse of the ceiling and the visibility. The thresholds are those of the NWS Aviation Weather Center; other countries use their own minima.
| Category | Ceiling | Visibility |
|---|---|---|
| LIFR | below 500 ft | less than 1 mile |
| IFR | 500 to below 1,000 ft | 1 to less than 3 miles |
| MVFR | 1,000 to 3,000 ft | 3 to 5 miles |
| VFR | above 3,000 ft | above 5 miles |
The ceiling is the lowest layer reported broken or overcast, or the vertical visibility into an obscured sky. Few and scattered layers do not count. KORD 251951Z 18008KT 1/2SM R28R/2400FT FG VV002 reports half a mile and a vertical visibility of 200 ft, so it is LIFR. ZBAA 251900Z 02004MPS 3000 BR NSC has no cloud, but 3,000 m is 1.9 statute miles, so it is IFR.
Is the wind in a METAR true or magnetic?
True. The first three digits of the wind group give the direction the wind blows from, referenced to true north. Runway numbers are magnetic, so a crosswind worked out directly from a METAR is off by the local magnetic variation. Wind read out by the tower or on the ATIS is magnetic.
Sources
Report format: FAA Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25C, 2023), chapter 13, aviation weather reports, and chapter 12 for the ceiling. Flight category thresholds: NWS Aviation Weather Center, GFA help page (aviationweather.gov/gfa/help), read 25 October 2026. Conversions: 1 statute mile is 1,609.344 m, 1 inHg is 33.8639 hPa. Parsing: the open-source metar-taf-parser library (MIT licence).
Questions from readers
What is the difference between METAR and SPECI?
A METAR is the routine report, issued on a regular schedule. A SPECI is a special report that can be issued at any time between routine reports when the weather changes significantly. The first row of the table shows which one you pasted.
What does CAVOK mean?
CAVOK stands for ceiling and visibility OK. It replaces the visibility, weather and cloud groups when visibility is good, there is no significant weather and no cloud of operational significance. The decoder shows it in the visibility row.
What does VV mean in a METAR?
VV is vertical visibility, reported when fog or another obscuration hides the sky. VV002 means 200 ft, and that value counts as the ceiling.
What do the numbers 18/09 mean?
They are the temperature and the dew point in whole degrees Celsius, so 18/09 is 18 C and 9 C. A minus sign is written M, so M02/M05 is minus 2 C and minus 5 C.
What is the difference between A3012 and Q1018?
Both are altimeter settings. A3012 is in inches of mercury (30.12 inHg) and appears in US reports, as in the KJFK example. Q1018 is in hectopascals (1,018 hPa, or 30.06 inHg) and appears in reports like the EGLL example. The decoder shows both units.
Does the decoder fetch live weather?
No. It decodes the text you paste and sends nothing anywhere. Take the report from an official source and check it is current before you rely on it.
What is the difference between a METAR and a TAF?
A METAR describes the weather now at an airport, a TAF forecasts it. To read a forecast, use the TAF decoder.
Related tools
- TAF decoder: reads the forecast that goes with the observation.
- Crosswind calculator: turns the report’s wind into crosswind and headwind for your runway.
- Cloud base calculator: estimates the base of cumulus from the temperature and dew point.
- Zulu time converter: converts the UTC time stamp to local time.
- Pressure altitude calculator: uses the altimeter setting from the report.
- Density altitude calculator: uses the report’s temperature and pressure for takeoff performance.
- Weather and time tools: the hub for the other weather and time pages.