Paste a raw METAR or SPECI aviation weather report and get every group explained in plain English: wind, visibility, runway visual range, weather, cloud layers, temperature, dew point, altimeter and the US remarks section, plus a VFR, MVFR, IFR or LIFR flight category badge.
Last updated:
Try an example:
Temperature first
Advertisement
Advertisement
How to use the METAR Decoder
Paste a raw METAR or SPECI into the box, for example from a flight planning app or the aviationweather.gov text page. You can paste several reports, one per line.
Read the summary and flight category: the colored badge shows VFR, MVFR, IFR or LIFR and the sentence explains why.
Check the group table to see what each code means, including runway visual range, cloud layers and the remarks section.
Enter a runway heading (like 31 or 310) to get headwind and crosswind components, including gusts.
Press Copy decoded text to paste the translation into notes, a briefing or a message.
How to read a METAR, group by group
Take METAR KJFK 211551Z 31014G22KT 10SM FEW045 BKN250 18/07 A3002 RMK AO2 SLP165 T01780072. The groups always appear in the same order:
Cover in oktas (FEW 1–2, SCT 3–4, BKN 5–7, OVC 8) and base in hundreds of feet above ground; VV002 = sky obscured, vertical visibility 200 ft
Temp/dew point
18/07
°C; M means minus, so M04/M06 = −4 °C / −6 °C
Altimeter
A3002 / Q1019
30.02 inHg or 1019 hPa
Remarks
RMK AO2 SLP165 T01780072
Automated station with precip sensor, sea-level pressure 1016.5 hPa, precise temperature 17.8 °C and dew point 7.2 °C
Flight categories at a glance
Category
Ceiling
Visibility
Chart color
VFR
above 3,000 ft
and
above 5 SM
Green
MVFR
1,000 – 3,000 ft
and/or
3 – 5 SM
Blue
IFR
500 – below 1,000 ft
and/or
1 – below 3 SM
Red
LIFR
below 500 ft
and/or
below 1 SM
Magenta
The ceiling is the lowest layer reported as broken (BKN), overcast (OVC) or vertical visibility (VV). FEW and SCT layers never form a ceiling, no matter how low they are.
Useful numbers derived from a METAR
Relative humidity comes from temperature and dew point with the Magnus formula: RH = 100 × e17.625·Td/(243.04+Td) ÷ e17.625·T/(243.04+T).
Temperature/dew point spread: a spread of 2 °C or less, especially with light wind in the evening, is a classic warning sign for fog or low stratus.
Estimated cumulus cloud base ≈ spread (°C) × 400 ft (about 1,000 ft per 2.5 °C). It is a rule of thumb for convective clouds, not a substitute for the reported layers.
Crosswind = wind speed × sin(angle between wind and runway); headwind = wind speed × cos(angle). METAR wind is relative to true north, while runway numbers are magnetic, so the result is approximate where magnetic variation is large.
Frequently asked questions
What is a METAR?
A METAR is a routine aviation weather observation from an airport or automated weather station, normally issued every hour around 50–55 minutes past the hour. It uses a compact code defined by the WMO and ICAO (with US differences in FAA and NWS rules) to report wind, visibility, weather, clouds, temperature, dew point and air pressure.
What is the difference between a METAR and a SPECI?
A SPECI is a special, unscheduled report issued between routine METARs when conditions change significantly, for example when visibility or the ceiling crosses a flight-category threshold, a thunderstorm begins or ends, or a wind shift occurs. It uses the same format as a METAR.
How are VFR, MVFR, IFR and LIFR determined?
They use the ceiling (the lowest broken, overcast or vertical-visibility layer) and the visibility. VFR: ceiling above 3,000 ft and visibility above 5 statute miles. MVFR: ceiling 1,000–3,000 ft and/or visibility 3–5 miles. IFR: ceiling 500 to below 1,000 ft and/or visibility 1 to below 3 miles. LIFR: ceiling below 500 ft and/or visibility below 1 mile. The worse of the two decides the category.
What does CAVOK mean?
CAVOK means Ceiling And Visibility OK: visibility of 10 km or more, no cloud below 5,000 ft or the highest minimum sector altitude (whichever is higher), no cumulonimbus or towering cumulus, and no significant weather. It is used outside the United States.
Are METAR times local time?
No. METAR times are always in UTC, also called Zulu time. The group 211551Z means the 21st day of the month at 15:51 UTC. The decoder also converts it to your device's local time.
What does A3002 or Q1019 mean?
Both are the altimeter setting. A3002 is 30.02 inches of mercury (used in the US and Canada), and Q1019 is 1019 hectopascals (used in most other countries). The altimeter setting is not the same as the sea-level pressure (SLP) in the remarks, which is reduced to sea level differently.
Can I use this decoder for flight planning?
It is a learning and convenience tool. Always get an official weather briefing and read the original report before flying, because unusual or local codes may not be fully decoded. Groups that are not recognized are clearly marked instead of being guessed.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.