METAR Codes Decoded: A Pilot's Guide to Reading Aviation Weather
Learn how to read and decode METAR weather reports. Understand aviation weather codes, visibility, cloud layers, and all the abbreviations pilots need to know.
What Is a METAR?
METAR (Meteorological Aerodrome Report) is a standardized format for reporting weather observations at airports and other observation sites. Issued at least hourly (or more frequently during rapidly changing conditions), METARs give pilots the critical weather information needed for safe flight operations.
If you've ever seen something like this:
KJFK 151856Z 32015G25KT 10SM FEW040 SCT250 07/M03 A3012 RMK AO2
...and wondered what it means, you're in the right place.
Anatomy of a METAR
Let's decode that METAR piece by piece:
Station Identifier
KJFK
The 4-letter ICAO identifier for the airport. In the US, these start with "K" (KJFK = New York JFK, KLAX = Los Angeles, KORD = Chicago O'Hare).
Date and Time
151856Z
- 15 = Day of the month
- 1856 = Time in 24-hour format
- Z = Zulu time (UTC)
So this observation was taken on the 15th at 18:56 UTC.
Wind
32015G25KT
- 320 = Wind direction (degrees from true north)
- 15 = Wind speed (knots)
- G25 = Gusts to 25 knots
- KT = Knots
Translation: Wind from 320° (northwest) at 15 knots, gusting to 25 knots.
Special wind codes:
- VRB = Variable direction (light winds)
- 00000KT = Calm (no wind)
- 320V010 = Wind variable between 320° and 010°
Visibility
10SM
Prevailing visibility in statute miles.
- 10SM = 10 statute miles (standard clear day)
- 3SM = 3 statute miles
- 1/2SM = Half a statute mile
- M1/4SM = Less than 1/4 statute mile
Weather Phenomena
This section describes current weather. If absent, no significant weather is occurring.
Intensity:
- - = Light
- (no symbol) = Moderate
- + = Heavy
- VC = In the vicinity (5-10 miles)
Descriptor:
| Code | Meaning |
|---|---|
| MI | Shallow |
| PR | Partial |
| BC | Patches |
| DR | Drifting |
| BL | Blowing |
| SH | Showers |
| TS | Thunderstorm |
| FZ | Freezing |
Precipitation:
| Code | Meaning |
|---|---|
| DZ | Drizzle |
| RA | Rain |
| SN | Snow |
| SG | Snow grains |
| IC | Ice crystals |
| PL | Ice pellets |
| GR | Hail |
| GS | Small hail |
| UP | Unknown precipitation |
Obscuration:
| Code | Meaning |
|---|---|
| BR | Mist (visibility 5/8-6 SM) |
| FG | Fog (visibility under 5/8 SM) |
| FU | Smoke |
| VA | Volcanic ash |
| DU | Dust |
| SA | Sand |
| HZ | Haze |
| PY | Spray |
Examples:
- -RA = Light rain
- +TSRA = Thunderstorm with heavy rain. The plus, minus or blank describes the precipitation, never the thunderstorm; METAR has no coding for a heavy thunderstorm
- FZRA = Freezing rain
- VCSH = Showers in the vicinity
- BR = Mist
Cloud Layers
FEW040 SCT250
Cloud coverage and height in hundreds of feet AGL (above ground level):
| Code | Coverage | Meaning |
|---|---|---|
| FEW | 1-2 oktas | Few clouds |
| SCT | 3-4 oktas | Scattered |
| BKN | 5-7 oktas | Broken |
| OVC | 8 oktas | Overcast |
| CLR | No clouds | Clear below 12,000 ft (automated) |
| SKC | No clouds | Sky clear (manual observation) |
FEW040 = Few clouds at 4,000 feet AGL SCT250 = Scattered clouds at 25,000 feet AGL
Special cloud types:
- CB = Cumulonimbus (thunderstorm clouds)
- TCU = Towering cumulus
Example: BKN025CB = Broken cumulonimbus at 2,500 feet
Temperature and Dew Point
07/M03
- 07 = Temperature: 7°C
- M03 = Dew point: -3°C (M = minus)
The closer these numbers are, the higher the humidity. When they match, fog is likely.
Altimeter Setting
A3012
- A = Altimeter setting in inches of mercury
- 3012 = 30.12 inches Hg
This is what you set in your altimeter for accurate altitude readings.
In other countries: You may see Q1023 which is pressure in hectopascals (millibars).
Remarks (RMK)
RMK AO2
Additional information that doesn't fit the standard format:
| Code | Meaning |
|---|---|
| AO1 | Automated station without precipitation discriminator |
| AO2 | Automated station with precipitation discriminator |
| SLP031 | Sea level pressure (1003.1 mb) |
| T00671028 | Precise temp/dewpoint (6.7°C / -2.8°C) |
| $ | Maintenance needed |
| PRESFR | Pressure falling rapidly |
| PRESRR | Pressure rising rapidly |
Special METAR Types
SPECI
A special observation issued when conditions change significantly between regular hourly reports:
SPECI KJFK 151923Z...
Issued when:
- Ceiling drops below/rises above certain thresholds
- Visibility changes significantly
- Thunderstorms begin or end
- Wind shift or significant change
AUTO
Indicates an automated observation with no human oversight:
KJFK 151856Z AUTO...
Automated stations may miss certain phenomena (like volcanic ash or tornadoes).
COR
A corrected observation replacing an earlier erroneous report:
KJFK 151856Z COR...
Reading Ceiling and Visibility
For VFR/IFR planning, focus on ceiling and visibility:
Ceiling = The height of the lowest BKN or OVC layer (or vertical visibility in obscured conditions)
| Category | Ceiling | Visibility |
|---|---|---|
| VFR | Over 3,000 ft | Over 5 SM |
| MVFR | 1,000-3,000 ft | 3-5 SM |
| IFR | 500-1,000 ft | 1-3 SM |
| LIFR | Under 500 ft | Under 1 SM |
Common METAR Examples
Clear Day
KLAX 151853Z 25010KT 10SM CLR 22/12 A2992
Los Angeles: Wind 250° at 10 knots, 10 miles visibility, clear skies, temp 22°C, dew point 12°C, altimeter 29.92
Foggy Morning
KSFO 151756Z 00000KT 1/4SM FG VV002 12/12 A3002
San Francisco: Calm winds, 1/4 mile visibility in fog, vertical visibility 200 feet, temp equals dew point (saturated air)
Thunderstorms
KDFW 152053Z 18025G40KT 3SM +TSRA BKN015CB OVC040 24/22 A2978
Dallas: Wind 180° at 25 gusting to 40 knots, 3 miles visibility in a thunderstorm with heavy rain, broken cumulonimbus at 1,500 feet, overcast at 4,000 feet
Winter Weather
KORD 151951Z 02020G30KT 1SM -SN BLSN BKN010 OVC020 M05/M08 A2965
Chicago: Wind 020° at 20 gusting to 30 knots, 1 mile visibility in light snow and blowing snow, broken clouds at 1,000 feet, overcast at 2,000 feet, temp -5°C
TAFs: Terminal Aerodrome Forecasts
While METARs report current conditions, TAFs forecast future conditions:
TAF KJFK 151730Z 1518/1624 32015G25KT P6SM SCT040
FM152200 28012KT P6SM BKN050
TEMPO 1600/1604 4SM -RA BKN025
Key TAF codes:
- FM = From (permanent change)
- TEMPO = Temporary fluctuation
- BECMG = Becoming (gradual change)
- PROB40 = 40% probability
Quick Reference Card
Wind: Direction (3 digits) + Speed + G (gusts) + KT Visibility: Number + SM (statute miles) Weather: Intensity + Descriptor + Type Clouds: Coverage + Height (hundreds of feet) + Type Temp/Dew: Temperature/Dew point in Celsius Altimeter: A + Setting in inches Hg
Always Verify with Official Sources
Aviation weather standards and METAR formats can be updated by regulatory bodies. While we strive for accuracy, pilots should always verify information with authoritative sources like the FAA's Aviation Weather Center, official FAA publications, and current AIM (Aeronautical Information Manual). For flight planning, always use certified weather briefing sources.
Decode METARs with WeatherAI
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- AI explanations - Ask "What does this METAR mean?"
- Flight condition indicators (VFR, MVFR, IFR, LIFR)
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Useful Next Stops
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Aviation Weather
Track METARs, TAFs, and airport conditions in a pilot-friendly layout.
Tool
Flight Rule Calculator
Classify VFR, MVFR, IFR, and LIFR conditions from ceiling and visibility.
Use Case
Weather App for Pilots
Follow the aviation workflow for METARs, TAFs, ceilings, and crosswinds.
Glossary
Ceiling
The height above ground of the lowest broken or overcast cloud layer, or vertical visibility into an obscuration.