Decoding the METAR, the Surface Observation Line You Read First and the Remarks Section Everybody Skips

A METAR is a routine surface weather observation - a snapshot of what the weather actually is right now at a specific airport, not a forecast. Reading it fluently tells you more about whether your flight should happen than almost anything else on your screen. The trick is decoding it in order, one group at a time, and never skipping the remarks section at the end.

Here is a real observation we’ll take apart, front to back:

KGAI 161753Z 21015G25KT 3SM BR SCT008 OVC015 18/17 A2992 RMK AO2 SLP132

If your eyes glazed over, that’s normal. Let’s make every group mean something.

What Does METAR Stand For, and Why Does It Matter?

The term comes from the French for “aviation routine weather report.” What matters most is that it’s an observation, not a forecast. A machine or a human looked outside and recorded the truth at that field at that moment. For what the weather is going to do, you need the TAF (forecast). The METAR only tells you where you’re starting from.

How Do I Read the Station Identifier and Time?

The first group, KGAI, is the station identifier. This one is Montgomery County Airport in Maryland. Every reporting station has one, and they can look dangerously similar in a list.

Read the whole identifier, every time. KGAI and KGOV are entirely different airports, and briefing the wrong field because two identifiers looked alike is a classic, avoidable mistake.

The next group, 161753Z, is the date and time of the observation:

• 16 is the day of the month - the 16th.
• 1753 is the time - 17:53.
• Z means Zulu, or Coordinated Universal Time (Greenwich), not your local time.

That timestamp is not decoration. A METAR is only considered routine for about an hour. An observation three hours old isn’t current weather - it’s history. Always convert the time to your local zone so you know how stale it is. 1753Z on the summer East Coast is about 1:53 in the afternoon - fresh and usable.

How Do I Interpret Wind, Including Gusts?

The wind group 21015G25KT breaks down like this:

• The wind is coming from 210 degrees (out of the southwest).
• It’s blowing at 15 knots.
• It’s gusting to 25 knots (that’s what the G means).

Two things deserve your attention. First, wind direction in a METAR is always referenced to true north, not magnetic. The wind you hear on the ATIS or from the tower is magnetic, because it’s referenced to the runway. Out West, where magnetic variation is large, that gap matters when you calculate your crosswind component.

Second, respect the gust. The spread from 15 to 25 knots is a 10-knot gust factor. When you brief this, ask the real question: what’s the crosswind component on the runway I’ll use, at the gust value, not the average? The gust is the number that will try to weathervane you on rollout.

The Airman Certification Standards expect you to maintain control up to the maximum demonstrated crosswind component for your airplane - and the METAR is where that homework starts.

One more wind note: if you see a group like 180V240, the V means the wind is variable in direction between those two headings. That’s your cue that the wind can’t make up its mind, and neither can the airplane on final.

What Does BR Mean, and How Do I Read Visibility?

Next is 3SM BR: visibility is 3 statute miles in mist. The contraction BR trips up nearly every student because it doesn’t stand for anything obvious in English - it comes from the French for mist.

Mist (BR) means visibility is reduced but sits between about 5/8 of a mile and 6 miles. If it were thicker than that - below 5/8 of a mile - you’d see FG for fog instead.

Three miles in mist on a summer morning tells a story: there’s moisture in the air, visibility is down, and if the temperature and dewpoint are close (we’ll check that next), it could get worse before it gets better - or burn off by mid-morning. The METAR won’t tell you which; that’s the TAF’s job.

How Do I Read Cloud Layers and Find the Ceiling?

The sky groups here are SCT008 (scattered at 800) and OVC015 (overcast at 1,500). The coverage words are precise, and examiners expect precision. Coverage is described in eighths of the sky:

• Few (FEW): 1–2 eighths
• Scattered (SCT): 3–4 eighths
• Broken (BKN): 5–7 eighths
• Overcast (OVC): 8 eighths (the whole sky)

Here’s the rule that matters for legality: a ceiling is the lowest broken or overcast layer. Scattered is not a ceiling. So in our METAR, the scattered layer at 800 feet is not the ceiling - the ceiling is the overcast at 1,500 feet.

A 1,500-foot ceiling with 3 miles of visibility in mist is exactly the kind of morning where a VFR pilot in Class E or G airspace should be running cloud-clearance and visibility minimums in their head. For a fresh private pilot, it’s also the kind of day to watch for another hour or have a solid plan B. Nobody got hurt waiting for the fog to lift with a cup of coffee in hand.

One detail on the heights: cloud bases are in hundreds of feet above ground level (AGL), not above sea level. 008 means 800 feet above the field. Pilots mix up AGL and MSL when they’re tired - and tired is exactly when weather bites.

What Do the Temperature and Dewpoint Tell Me?

The group 18/17 is temperature over dewpoint, in degrees Celsius: 18°C temperature, 17°C dewpoint.

Look at that spread - just 1 degree. When temperature and dewpoint converge, the air is saturated, and saturated air makes clouds and fog. A 1-degree spread with mist already reported is the sky telling you visibility could drop.

This is one of the most useful things in the entire METAR, and it’s just two numbers. Learn to glance at the temperature–dewpoint spread first thing, every time. A tight spread in the morning is a fog warning. A tight spread at dusk with the temperature falling is a fog warning with a countdown timer.

If either number has an M in front, like M03, the M means minus - minus 3 Celsius. Near-freezing temperatures with visible moisture around bring airframe icing into the conversation, which is a whole different briefing.

What Is the Altimeter Setting?

The group A2992 is your altimeter setting: 29.92 inches of mercury. The A flags it as an altimeter setting in inches. You’ll dial that exact number into the Kollsman window so your altimeter reads field elevation on the ground. Get it wrong, and every altitude you fly is wrong with it.

For reference, standard pressure is 29.92, so this is an ordinary day pressure-wise.

What’s Hiding in the Remarks Section?

Everything after RMK is extra information - and there’s real value there that most pilots scroll right past.

In our example, AO2 tells you this is an automated station with a precipitation discriminator - it can tell the difference between rain and snow. An AO1 station cannot. This matters because an automated station has limits: it looks at one small patch of sky straight up and can miss a cloud layer off to the side or distant weather. When you see AO2, a machine wrote the report - so keep your own eyes open on arrival.

Then SLP132 is sea level pressure: 1013.2 millibars. You mostly won’t need it in a light single, but it’s how meteorologists compare pressure across a region.

When there’s a human at the station, the remarks are even richer - a lightning report, a distant thunderstorm and its movement, the peak wind gust in the last hour, the exact time a fog bank rolled in, or a variable-ceiling notation. On a marginal day, the remarks can be the difference between an informed go and a nasty surprise. Read them every time.

How Do I Put the Whole METAR Together?

Don’t read a METAR letter by letter - read it as a story. Here’s our example, briefed the way you’d actually do it:

Montgomery County, mid-afternoon observation, fresh. Wind out of the southwest, 15 gusting 25, so I’ve got a gusty crosswind to plan for depending on the runway. 3 miles in mist - a soft, hazy day. Scattered at 800, but my real ceiling is overcast at 1,500. Temperature and dewpoint just 1 degree apart, so this moisture isn’t going anywhere fast and could thicken. Altimeter ordinary at 29.92. Remarks say automated station, so I’ll trust it but verify with my own eyes on arrival.

That’s a 30-second read once you’ve built the skill - and the skill is nothing but reps. Pull up your home field’s METAR every morning, flying or not. Read it out loud and decode it before you look at the plain-language translation your app gives you. In a month it stops being Scrabble tiles and becomes a sentence.

On the checkride, the examiner isn’t trying to trap you. They want a pilot who can read that line, explain it in plain English, and then say what they’re going to do about it. That second part - the decision - is the whole ballgame. You can practice for free anytime at the Aviation Weather Center.

Key Takeaways

• A METAR is an observation, not a forecast - it tells you the current weather, while the TAF tells you what’s coming.
• Always check the Zulu timestamp and convert to local time; a METAR is only routine for about an hour.
• A ceiling is the lowest broken or overcast layer - scattered layers don’t count. In our example the ceiling is OVC at 1,500 feet, not the scattered layer at 800.
• Wind direction is true north in a METAR (magnetic on the ATIS/tower), and you should brief crosswinds at the gust value, not the average.
• A tight temperature–dewpoint spread signals possible fog, and the remarks section (like AO2 and SLP) holds details that can make or break a marginal-day decision.