How do you read a METAR?

Left to right: station, day and time in UTC, wind (direction in degrees true and speed in knots, with G for gusts), visibility in statute miles, present weather, sky cover with bases in hundreds of feet above ground, temperature and dewpoint in Celsius (M means minus), then the altimeter setting. Remarks follow RMK.

What do VFR, MVFR, IFR and LIFR mean on a METAR?

They are flight categories from the ceiling and visibility. VFR is a ceiling above 3,000 feet and visibility above 5 miles; MVFR is 1,000 to 3,000 feet or 3 to 5 miles; IFR is 500 to below 1,000 feet or 1 to below 3 miles; LIFR is below 500 feet or below 1 mile. They are chart categories, not the Part 91 weather minimums.

What counts as a ceiling?

The lowest layer reported as broken (BKN) or overcast (OVC), or a vertical visibility (VV) into an obscuration. Few and scattered layers are not ceilings, however low they are.

Is this decoder an official weather source?

No. It translates the text you paste, in your browser. Get the METAR from an official source such as aviationweather.gov or a Flight Service briefing, and always read the raw report too.

Pilot tool

METAR decoder

A METAR is a routine airport weather observation, written in a fixed order: station, time, wind, visibility, weather, clouds, temperature and dewpoint, altimeter, then remarks. Paste one below to read it in plain English, with the ceiling and the VFR, MVFR, IFR or LIFR flight category worked out for you.

Paste a METAR or SPECI

Try an example

Decoded in your browser. Nothing you paste leaves this page. Example reports are illustrative, not current weather.

MVFR

Ceiling 1,000 to 3,000 ft and/or visibility 3 to 5 SM

Station: KDEN
Observed: Day 10, 18:53 UTC
Wind: From 330° at 18 kt, gusting 29 kt, varying between 300° and 360°33018G29KT 300V360
Visibility: 10 statute miles10SM
Weather: None reported
Sky: Broken at 2,800 ft AGLBKN028
Overcast at 5,000 ft AGLOVC050
Ceiling: 2,800 ft AGL
Temperature: -2°C (28°F)
Dewpoint: -8°C (18°F)spread 6°C
Altimeter: 29.88 inHg (1012 hPa)
Remarks: AO2

How it works

Every group in a METAR has a shape the decoder recognises. A wind group like 33018G29KT is direction, speed and gust in knots, with 300V360 after it meaning the direction is varying across that sector. Visibility ends in SM for statute miles in the United States, and can be a whole number and a fraction (1 1/2SM), a less than (M1/4SM) or a more than (P6SM). Elsewhere it is four digits of metres, and 9999 means 10 kilometres or more.

Present weather stacks an intensity (light −, heavy +, or VC for in the vicinity), an optional descriptor such as TS for thunderstorm or FZ for freezing, and one or more phenomena such as RA for rain or BR for mist. Sky cover is FEW, SCT, BKN or OVC with the base in hundreds of feet above the ground, so BKN028 is broken at 2,800 feet. CB or TCU after a layer flags cumulonimbus or towering cumulus.

Temperature and dewpoint are whole degrees Celsius with M for minus. A close spread warns of fog or low cloud. A is the altimeter in inches of mercury (A2988 is 29.88) and Q is hectopascals. Everything after RMK is shown as written, because remarks vary by station.

The rules

Ceiling first, then category.

Ceiling = the lowest BKN, OVC or VV layer. FEW and SCT never form a ceiling.

LIFR: ceiling below 500 ft AGL and/or visibility below 1 SM.

IFR: ceiling 500 to below 1,000 ft and/or visibility 1 to below 3 SM.

MVFR: ceiling 1,000 to 3,000 ft and/or visibility 3 to 5 SM.

VFR: ceiling above 3,000 ft and visibility above 5 SM.

The worse of ceiling and visibility sets the category. These are the station plot categories in AC 00-45H Table 3-14; the FAA notes they are not flight rules and are separate from the Part 91 basic VFR weather minimums.

Source

Worked example

KDEN 101853Z 33018G29KT 300V360 10SM BKN028 OVC050 M02/M08 A2988

Denver, on the 10th at 18:53 UTC. Wind from 330° at 18 knots gusting 29, varying between 300° and 360°. Visibility 10 statute miles. Broken clouds at 2,800 feet and overcast at 5,000. Temperature minus 2 °C, dewpoint minus 8 °C. Altimeter 29.88.

The ceiling is the broken layer at 2,800 feet, which is within 1,000 to 3,000 feet, so the category is MVFR even with 10 miles of visibility. With an 11 knot gust spread, it is also worth running through the crosswind calculator for the runway in use.

Questions

How do you read a METAR?: Left to right: station, day and time in UTC, wind (direction in degrees true and speed in knots, with G for gusts), visibility in statute miles, present weather, sky cover with bases in hundreds of feet above ground, temperature and dewpoint in Celsius (M means minus), then the altimeter setting. Remarks follow RMK.
What do VFR, MVFR, IFR and LIFR mean on a METAR?: They are flight categories from the ceiling and visibility. VFR is a ceiling above 3,000 feet and visibility above 5 miles; MVFR is 1,000 to 3,000 feet or 3 to 5 miles; IFR is 500 to below 1,000 feet or 1 to below 3 miles; LIFR is below 500 feet or below 1 mile. They are chart categories, not the Part 91 weather minimums.
What counts as a ceiling?: The lowest layer reported as broken (BKN) or overcast (OVC), or a vertical visibility (VV) into an obscuration. Few and scattered layers are not ceilings, however low they are.
Is this decoder an official weather source?: No. It translates the text you paste, in your browser. Get the METAR from an official source such as aviationweather.gov or a Flight Service briefing, and always read the raw report too.

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