Reading a Raw METAR From the Top, Decoding One Line of Code Field by Field So the Weather Talks Back to You

A raw METAR is an aviation routine weather observation that reports what the sky was actually doing at a specific field and moment - not a forecast. You read it left to right in fixed groups: station identifier, date and time, wind, visibility, present weather, sky condition, temperature and dew point, and altimeter setting. Once you decode each group in order, that “keyboard-smash” string becomes a clear picture of a place, a wind, a ceiling, and a story.

What Is a METAR, and How Is It Different From a TAF?

A METAR is an aviation routine weather report - an observation of current conditions. That word matters: a METAR tells you what the weather is doing right now, or more precisely, what it was doing at the moment it was observed. It is not a forecast.

The forecast is the TAF (Terminal Aerodrome Forecast), which is a separate product. Keep the two straight: METAR looks at the present, TAF looks ahead.

Most METARs are issued once an hour, usually a few minutes before the top of the hour. When conditions change quickly, a special report is issued in between and carries the label SPECI up front instead of METAR.

How Do I Read a Raw METAR Line by Line?

Here is our working example, read from the page:

KGSO 011753Z 24015G22KT 10SM FEW035 BKN070 28/14 A3012

Each group has a job. Read them in order and the string decodes itself.

The Station Identifier

The line opens with a four-letter station identifier - here, KGSO. In the lower 48 states, airport identifiers are three characters, but on a weather report they get a K added to the front to make four. If your field has a three-letter identifier, it simply wears a K as a hat on the METAR.

Regional prefixes differ: Alaska starts with PA, Hawaii with PH, and Canada with C. For mainland flying, see the K and mentally peel it off.

Confirm the station before you read a single number. It’s common for a pilot to brief the weather beautifully and only later realize it was for a similar-sounding airport 40 miles away. Read the station first. Confirm it. Then continue.

The Date and Time

Next is a six-digit number followed by Z for Zulu: 011753Z. The first two digits are the day of the month - the 1st. The next four are the time - 1753 - in Zulu time (Coordinated Universal Time), the single clock all of aviation shares.

So this observation was taken at 1753Z, seven minutes before 1800Z. That timing marks it as a routine top-of-the-hour observation, taken just before the hour rolls over.

The timestamp matters because a METAR is a snapshot, and snapshots get old. If 90 minutes have passed since the observation, you’re looking at history, not current weather. Convert the Zulu time to local, figure out how old the report is, and ask whether the sky has had time to change. On a summer afternoon, an hour is plenty of time for a clear field to grow a thunderstorm.

The Wind

The wind is a five- or six-digit block, sometimes with a G in the middle: 24015G22KT.

• The first three digits, 240, are the direction the wind is coming from, in degrees.
• The next two digits, 15, are the speed in knots.
• G22 means the wind is gusting to 22 knots.

So the wind is from 240 degrees at 15 knots, gusting to 22.

One catch trips up every new pilot: the METAR wind is referenced to true north, while the wind the tower gives you over the radio and the wind on the ATIS are referenced to magnetic north. Same wind, two reference points. Depending on local magnetic variation, the printed and spoken winds may not match exactly - and both are correct.

Now think like a pilot. If your runway runs roughly north–south and the wind is from the southwest at 15 gusting 22, you have a gusty crosswind. That’s the cue to run the crosswind component math and to check whether the 7-knot gust spread is inside your personal limits and the airplane’s demonstrated crosswind value.

Two variations to know: VRB means the wind direction is variable (usually in light wind), and 00000KT means calm.

The Visibility

Visibility here is 10SM - 10 statute miles, the top of the scale for most U.S. reports.

When visibility drops, you’ll see lower whole numbers like 3 (three statute miles) or fractions such as 1 1/2 or 3/4 written directly in the string. In very low visibility near a specific runway, an RVR group appears - an R followed by a runway number and a distance in feet. That’s a laser-measured runway visual range, most relevant to instrument pilots flying approaches to minimums.

For VFR flying, visibility is one of the two numbers - along with cloud height - that decides whether it’s a legal and smart day to go.

Present Weather (When It Appears)

Our clean example has no present weather group, which is the sky’s way of saying nothing significant is falling or blocking the view. When weather turns, this group sits between visibility and clouds and tells you what’s happening:

• RA – rain
• SN – snow
• FG – fog
• BR – mist (the thinner cousin of fog)
• TS – thunderstorm

Modifiers refine it: a minus (−) means light, a plus (+) means heavy, SH means showers, and FZ means freezing. So −RA is light rain, and +TSRA is a thunderstorm with heavy rain - a very different flight-planning conversation. When present weather shows up, read it slowly.

The Sky Condition

Our sky groups are FEW035 and BKN070. Cloud layers are reported with a three-letter coverage code followed by a height, and that height is in hundreds of feet above ground level (AGL) - above the airport, not above sea level.

So FEW035 is a few clouds at 3,500 feet AGL, and BKN070 is a broken layer at 7,000 feet AGL.

The coverage codes climb a ladder:

• SKC/CLR – clear
• FEW – a few clouds
• SCT – scattered
• BKN – broken (more than half the sky)
• OVC – overcast (whole sky covered)

Here’s the key rule: a ceiling is the lowest broken or overcast layer. In our report, the FEW at 3,500 is decoration - it does not make a ceiling. The ceiling is the broken layer at 7,000 feet, because broken is the first layer thick enough to count.

The ceiling matters because your cloud clearance and minimum ceiling requirements for the airspace key off that lowest broken or overcast layer. Ten miles of visibility does you no good if the ceiling has come down on your head.

Watch for one special case: VV followed by a height is not a cloud layer. It’s vertical visibility into an indefinite ceiling - the sky is obscured by fog or heavy precipitation, and the number is how far up you can see before it all goes white. Treat it with respect.

The Temperature and Dew Point

This group is two numbers separated by a slash: 28/14. Both are in degrees Celsius - temperature 28°C, dew point 14°C. An M in front of either number means minus (below zero); M03 would be 3 below.

The relationship between the two is one of the most useful things on the report. When temperature and dew point are close together, the air is nearly saturated - your fog and low-cloud warning. When they’re far apart, like 28 and 14, the air is dry and fog is not on the menu.

The practical trick is to watch the spread over successive reports. If temperature and dew point are marching toward each other as the sun goes down, you may be watching fog form an hour before it happens.

The Altimeter Setting

The last group is A3012 - an A followed by four digits. The A means the setting is in inches of mercury, read with an implied decimal in the middle: 30.12 inches of mercury. That’s the pressure you dial into the Kollsman window so your altimeter reads true field elevation on the ground.

Fly overseas and you’ll see a Q instead, giving pressure in hectopascals. In the States, look for the A and think inches.

What Does the Whole METAR Tell Me Once It’s Decoded?

Put it back together: at KGSO, observed at 1753Z (a fresh top-of-the-hour report), the wind is from the southwest at 240° true, 15 gusting 22 - a gusty crosswind for many runways. Visibility is a clean 10 miles, with a few harmless clouds at 3,500 feet and a real ceiling, broken, at 7,000 feet. It’s warm and dry at 28/14, so no fog worries, and the altimeter is 30.12.

That’s a flyable day with one thing to think hard about: the gusty crosswind. And you got there yourself, left to right, one group at a time.

How Do I Build the Skill of Reading Raw METARs?

The homework costs nothing. Every day, whether you fly or not, pull up the raw METAR for your home field and read it out loud before looking at any translation. Do it for a week, and you’ll read the sky the way you read a road sign - without slowing down.

This is exactly what the Airman Certification Standards (ACS) expect. When the ACS asks you to obtain and interpret weather, the examiner wants a pilot who can look at raw data and tell the story - not one who reads a translation back like a menu. On a checkride, there is no translate button.

Key Takeaways

• A METAR is an observation of current weather, issued about once an hour; a SPECI is a special report between the hourly ones, and a TAF is the forecast.
• Read every METAR in the same fixed order: station, date/time, wind, visibility, present weather, sky, temperature/dew point, altimeter.
• METAR wind is referenced to true north; tower and ATIS winds are magnetic, so the printed and spoken directions can differ.
• A ceiling is the lowest broken (BKN) or overcast (OVC) layer - FEW and SCT layers don’t count.
• Cloud heights are AGL in hundreds of feet, temperatures are in Celsius, and a close temperature/dew point spread is your fog warning.