METAR and TAF decoder
Paste a raw METAR or TAF report and read it in plain language: wind, visibility, weather, clouds, temperature, altimeter and forecast periods.
Runs entirely in your browser
For learning and quick reading only. Not for flight planning or navigation: always use official briefings. Remarks (RMK) are shown as written, and any group the decoder does not understand is listed, never guessed.
How to decode a METAR or TAF
- Paste the raw report into the box, starting with METAR, SPECI, TAF or the four-letter station code. Several reports separated by = or on separate lines are decoded one after another.
- Read the breakdown below: each group of the code is translated into words, with units converted to knots, km/h, feet and metres, °C and °F, hPa and inHg.
- Check the flight category and any line marked as not decoded. Unknown groups are shown exactly as written.
How the decoder reads a report
A METAR or TAF is a string of space-separated groups in a fixed order, defined by ICAO Annex 3 and WMO Manual on Codes No. 306 (FM 15 METAR and FM 51 TAF) and, for the United States, by the FAA Aeronautical Information Manual 7-1-30. The decoder reads the station code, the day and time in UTC (DDHHMMZ), the wind (direction, speed, gusts and variation), the visibility in metres or statute miles, runway visual range, present weather, cloud layers, vertical visibility, temperature and dew point, and the altimeter setting (Q is hPa, A is inHg in hundredths).
Weather codes combine an intensity (- light, + heavy, VC in the vicinity), descriptors (TS, SH, FZ and others) and phenomena (RA rain, SN snow, FG fog, BR mist and so on). Cloud groups give the amount (FEW, SCT, BKN, OVC) and the base in hundreds of feet above ground level, with CB or TCU for convective cloud. Relative humidity is estimated from the temperature and dew point with the Magnus formula, es = 6.1094 e^(17.625 T / (T + 243.04)), so it is approximate.
Flight categories follow the FAA definitions: the ceiling is the lowest broken or overcast layer or vertical visibility, and the category is set by the worse of ceiling and visibility. For a TAF, each base or change group is decoded on its own, with its time range in UTC and its own category. Times are given as a day of the month and a UTC time because the reports do not carry a month or year.
Not for flight planning or navigation. This is an educational reader. Always get weather from an official source before flying.
Questions
What is the difference between a METAR and a TAF?
A METAR is an observation of the weather at an airport right now, usually issued every hour (a SPECI is an unscheduled update after a significant change). A TAF is a forecast for the airport, normally covering 24 to 30 hours, split into a base forecast and change groups.
How do I read the wind group, such as 29016G25KT?
The first three digits are the direction the wind blows from, in degrees true (290 is west-northwest), the next two or three digits are the speed (16), G adds the gust speed (25), and the last letters are the unit: KT for knots, MPS for metres per second, KMH for kilometres per hour. VRB means variable direction; 00000KT is calm.
What do the TAF change groups mean?
FM (from) starts a new set of conditions at a given time and replaces everything before it. BECMG means a gradual change during the stated period. TEMPO means short-lived fluctuations that last less than an hour at a time and under half of the period. PROB30 and PROB40 give the probability of the conditions that follow. INTER is an older word for TEMPO.
How are the flight categories worked out?
The decoder uses the US FAA thresholds from the lowest broken or overcast cloud layer (the ceiling) and the visibility: VFR above 3,000 ft and 5 SM, MVFR from 1,000 to 3,000 ft or 3 to 5 SM, IFR from 500 to under 1,000 ft or 1 to under 3 SM, and LIFR below 500 ft or 1 SM. CAVOK counts as VFR. Other countries use different limits, so treat it as a guide.
Why is part of my report shown as not decoded?
The decoder covers the core ICAO and FAA groups. Regional groups, military colour codes, runway state groups and anything misspelled are listed as written instead of being guessed. Remarks after RMK are never interpreted.
Does the page send my report anywhere?
No. The report is decoded by JavaScript in your browser, and nothing is uploaded. If you want to decode reports from code, the decode API in the guide below does the same job.