Every hour, thousands of weather stations around the world broadcast a short, coded weather report called a METAR. It looks like gibberish at first glance:
METAR KLGA 121756Z 31012G18KT 10SM FEW045 SCT250 08/M03 A3024 RMK AO2
But once you know the format, you can decode current conditions at any station in seconds. This guide breaks it down piece by piece.
What is a METAR?
METAR stands for Meteorological Aerodrome Report. It's a standardised observation format used by airports, military airfields, and weather stations worldwide. METARs are issued every hour (sometimes more frequently during severe weather) and are the primary source for:
- Pilots planning flights
- Weather services validating forecasts
- Anyone who needs ground-truth weather data
💡 Tip: DailyHigh pulls METAR observations directly from official sources to track daily high temperatures at major airport stations worldwide.
Anatomy of a METAR
Let's decode that example step by step:
METAR KLGA 121756Z 31012G18KT 10SM FEW045 SCT250 08/M03 A3024 RMK AO2
| Segment | Meaning |
|---|---|
METAR |
Report type (routine observation) |
KLGA |
Station identifier (ICAO code): LaGuardia Airport, New York |
121756Z |
Day and time: 12th of the month, 17:56 UTC |
31012G18KT |
Wind: from 310° at 12 knots, gusting to 18 knots |
10SM |
Visibility: 10 statute miles |
FEW045 |
Clouds: few at 4,500 feet |
SCT250 |
Clouds: scattered at 25,000 feet |
08/M03 |
Temperature 8 °C / Dewpoint −3 °C |
A3024 |
Altimeter: 30.24 inHg |
RMK AO2 |
Remarks: automated station with precipitation sensor |
Station identifier (ICAO code)
Every station has a four-letter ICAO code. The first letter indicates the region:
- K: contiguous United States (KLGA, KORD, KATL)
- C: Canada (CYYZ)
- E: Northern Europe (EGLC, London City Airport)
- L: Southern Europe (LTAC, Ankara)
- R: East Asia (RKSI, Incheon/Seoul)
- N: South Pacific (NZWN, Wellington)
- S: South America (SAEZ, Buenos Aires)
Date and time
The group 121756Z means the 12th day of the current month at 17:56 Zulu (UTC). METARs always use UTC. No timezone offsets.
Wind
Wind is reported as a five-digit (or more) group:
- 31012KT: direction 310°, speed 12 knots
- G18: gusts to 18 knots
- VRB03KT: variable at 3 knots (light and shifting)
- 00000KT: calm
Visibility
In the US, visibility is in statute miles (e.g. 10SM). Internationally, it's in metres (e.g. 9999 = 10 km or more).
Cloud layers
Clouds are reported from lowest to highest:
| Code | Meaning | Coverage |
|---|---|---|
SKC / CLR
|
Clear | 0/8 |
FEW |
Few | 1–2/8 |
SCT |
Scattered | 3–4/8 |
BKN |
Broken | 5–7/8 |
OVC |
Overcast | 8/8 |
The number after the code is the altitude in hundreds of feet AGL. So SCT250 = scattered clouds at 25,000 ft.
Temperature and dewpoint
Reported in Celsius, separated by a slash. An M prefix means negative:
-
08/M03→ temperature 8 °C, dewpoint −3 °C -
M02/M05→ temperature −2 °C, dewpoint −5 °C
The gap between temperature and dewpoint tells you about humidity. A narrow spread means higher relative humidity.
Why the daily high matters
For temperature tracking, the most important number in a METAR is the temperature field. Over the course of a day, the highest temperature reported across all hourly METARs becomes the daily high, the number that weather services, researchers, and forecasters use as the official maximum.
ℹ️ Info: DailyHigh tracks every METAR observation throughout the day and records the peak temperature automatically. You can see the full observation timeline on any station's history page.
Special weather codes
METARs can also include present weather phenomena between visibility and cloud groups:
| Code | Meaning |
|---|---|
RA |
Rain |
SN |
Snow |
FG |
Fog |
BR |
Mist |
TS |
Thunderstorm |
HZ |
Haze |
+RA |
Heavy rain |
-SN |
Light snow |
These can be combined: +TSRA means heavy thunderstorm with rain.
How to look up a METAR
You can access raw METARs from several sources:
- Aviation Weather Center at aviationweather.gov
- NOAA Weather for raw METAR feeds
- DailyHigh parses and displays METAR observations with temperature charts and daily high tracking for all tracked stations
Summary
METARs pack a lot of information into a compact format. Here's the quick reference:
TYPE STATION DATETIME WIND VISIBILITY [WEATHER] CLOUDS TEMP/DEW PRESSURE REMARKS
Once you can read METARs, you have direct access to the same ground-truth data that pilots, forecasters, and weather models rely on. No intermediary, no interpretation, just raw observations from the station.
Want to see live METAR data in action? Check out any of our tracked stations to see real-time observations and daily high tracking.
Originally published on DailyHigh. DailyHigh tracks daily high temperatures at major airport weather stations worldwide using real-time METAR observations.
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