Lesson 21: Understanding and Decoding METAR Reports 

Welcome Back! Today, we’ll dive deeper into weather reports for pilots, and how to decode them. 

METAR and TAF reports are two types of aviation weather reports used by pilots and meteorologists to understand current and forecasted weather conditions at airports.

So, it’s pretty cool that pilots have their very own way to get intel on the weather. 

Sounds cool! But why do these reports only show the weather around airports? 

These reports only show the weather around airports because they are meant to give pilots and air traffic controllers the current weather conditions at airports to ensure safe takeoffs, landings, and flights.

Nice! That makes sense. So, what’s the actual difference between a METAR and TAF report? 

Great question! METAR Reports provide real-time weather information for an airport, helping pilots know what the weather is like right now.

And TAF Reports provide a weather forecast for the future (for the next 24 to 30 hours) at an airport. This helps pilots plan for expected weather conditions.

Awesome! So METAR Reports share the current weather, and TAF Reports share future weather. 

Exactly! Pilots use both METAR and TAF Reports to plan their flights and identify potentially hazardous weather.  

But to understand them, we have to learn how to decode them. So today, we’ll only focus on METAR Reports, and in the next lesson, we’ll cover TAF Reports. 

Sounds good! So, let’s focus on METAR Reports and understand what they are and look like.  

A METAR Report is a special kind of weather report for pilots, that provides detailed information about the current weather at airports in real-time!

Meteorologists and pilots use it to know what's happening with the weather in the moment.

METAR Reports provide up-to-date weather information, which is essential for immediate decision-making.

Metar Reports are issued every hour, ensuring that pilots and meteorologists have the latest intel on weather.

METAR Reports are used all over the world! They give the same type of weather information for airports everywhere, so pilots and weather experts can understand and use the data no matter where they are! 

If the weather changes in a really bad way, a special METAR report (labeled SPECI) might come out any time between the regularly scheduled hourly reports.

Can you guess what ‘METAR’ stands for? 

Meteor Tracking and Analysis Report 

Meteorological Aerodrome Report

Mountain Expedition Terrain Assessment Record

Marine Environmental Temperature and Rainfall

Nice! Well, what happens to a METAR if there’s really bad or  dangerous weather up ahead? 

That is a great question! And a really important one.
If the current weather is really bad, pilots are sent a special report that we call a SPECI Report!  

SPECI Reports are issued when there are significant changes in weather conditions that occur between the regular hourly METAR reports.

SPECI Reports provide updated information to pilots and weather specialists about important weather changes that could impact aviation safety and operations.

Can you guess what ‘SPECI’ stands for? 

Soggy Penguin Extravaganza Celebration Index

Special Weather Report

Special Environmental Climate Inspection

Super Powerful Elephant Circus Information

Yup! It’s as simple as it sounds. It’s a special report for special weather that pilots can get between hourly METAR reports, if the weather gets bad. 

How often are METAR Reports Issued?

Every hour

METAR Reports

Every 12 Hours

Every 30 Years

Decoding METAR Reports 

Great work so far! Now that we understand what METAR Reports are, let’s learn how to decode them! It’s intense, but we got this. 

Awesome! Well, what does a METAR report actually look like? I’m kind of scared now. 

A METAR report is a string of text that shows pilots  information about the current weather at an airport - and we’ve covered a lot of this information before! 

METAR Reports have a lot of information on them – including a funny-sounding type of time: ZULU Time! Let’s define this before we look at a METAR Report. 

Zulu Time, also known as Coordinated Universal Time (UTC), is the time standard used worldwide, especially in aviation and military. It's the same everywhere, without any time zone adjustments, so there is consistency across different locations.

They look like a bunch of jumbled up letters, but they actually contain lots of useful weather information! Let’s walk through this example of a METAR report:

A METAR report is a string of text that shows pilots  information about the current weather at an airport. Here's an example of a METAR report:

Here’s the big reveal! You’re going to be so proud of yourself once we figure out how to decode this! 

Let’s quickly walk through what each code means. Then, we’ll decode them step-by-step! 

Just a quick note – this is what professional pilots in the sky use every single day, so it’s pretty cool that we get to learn about it, too. 

METAR KJFK 121651Z 18015G25KT 10SM SCT020 BKN250 30/20 A3005 RMK AO2 SLP177

What are your first reactions to this? Share an emoji in the chat. 

… I usually get my weather information from
the weather guy on TV or the app on my phone.
Why are METAR reports written… like this?! 

Great question! Let’s look at a few reasons why, and then start decoding a METAR Report. 

These weather reports use a standard format that everyone around the world understands. This helps pilots and meteorologists from different countries read and use the information easily.

- Global Consistency -

These reports use short codes and abbreviations to share a lot of information quickly. This makes it easy to read and send the reports fast, which is important for safety.

- Quick and Efficient -

Using the same codes throughout the world helps avoid misunderstandings. Everyone knows exactly what the weather conditions are.

- Clarity -

Many weather stations and systems automatically create these reports. The standardized format helps these systems work smoothly and provide updates directly to pilots.

- Automation -

Let’s start exploring what each section means. There are about 8 of them in a METAR Report! 

METAR KJFK 121651Z 18015G25KT 10SM SCT020 BKN250 30/20 A3005 RMK AO2 SLP177

Each piece tells us certain details about the location, time, and weather.

The Type of Weather Report 

The Airport Code

Date and Time

Wind Info

Visibility 

Cloud Info

Temperature and Dew Point

Altimeter Settings

Remarks (Notes) 

Awesome! Now that we vaguely know what each section represents, let’s start decoding them. 

The Type of Report 

This can say either METAR, METAR / SPECI, or TAF! 

The first thing we see tells us what kind of report it is.
If this was a special report, it would say SPECI, instead.

The Airport Code 

Place / Airport 

Which airport the report was made from. 

This is a 4-letter ICAO airport code — each airport has a unique identifier code!

This report came out of the JFK Airport, or the John F. Kennedy International Airport!

Hmm… If we need to know about the weather at the JFK airport, why not show the weather in New York City (NYC)? Wouldn’t that be easier? 

The specific airport info is important in a METAR because even in the same city, weather might be different around different airports. 

It helps plane pilots pinpoint the exact weather conditions, like wind direction, more precisely. Imagine if they had to guess this stuff!  

The specific airport code is important to name in a METAR because even in the same city, weather might be different around different airports. 

Since understanding weather is critical to plane pilots, it helps them pinpoint the exact weather conditions, like the wind direction, more precisely. Imagine if they had to guess!  

Date & Time

This tells you the date and time the report was made! In Zulu / UTC time, of course. 

It’s important to know what time a METAR came out, so we know whether the information is relevant or not.

Let’s pause and decode what this section means! 

121651Z

‘12’ is the day of the month

‘16:51’ is the time (in the UTC time zone)

"Z" means Zulu time
(another name for UTC).

Let’s pause and decode these time zones! 

You might have heard of UTC before! UTC stands for Coordinated Universal Time, and it’s a standard way to tell time all around the world, so no one gets mixed up.  

In the USA, we use AM/PM time. This splits the day into two 12-hour parts. Most other countries use what we call the 24-hour clock, or ‘Military Time.’  

With the 24-hour clock, the day starts at 0:00 and ends at 24:00. They don’t have AM or PM! Seems easier than dividing the day into two, honestly. 

The military and pilots use this standard system (UTC, or the 24 hour system) instead. It makes time clearer for everyone and avoids any confusion between morning and night times.

So, that’s also why you don’t see AM or PM at the end of the time – you don’t need it! 

Military time can be confusing to most Americans – we never really use it! But here’s an example:

1:00 PM our time would be 13:00 in military time. 

And, if you ever need to calculate the time, there are calculators you can use online for free!  

Huh, that’s starting to make sense. But why do we write time down in both UTC and Z?

Excellent question! "Zulu time" and "UTC" are the same time standard. Adding a Z at the end just tells pilots that the time is told in Zulu (or UTC) time, just so no one is confused.  

This tells you the date and time the report was made! In Zulu / UTC time, of course. 

Heads Up! 

Who wrote it

By the way, if you see ‘AUTO’ in a report, that just means that the report was sent out by a computer – not a human! 

And if you see a METAR report that does not have
“AUTO” in it, that means a human wrote it!

Yay Humans <3 

AUTO is important to know. Observations from a computer can be useful during chiller times. But when the weather is more intense, METARs sent from humans can be more accurate. 

Awesome! I love humans, too. Now, let’s get back to the METAR show. Next up, let’s talk about the wind. 

Wind Info

This tells you information about the wind! It says the direction it’s coming from and its speed. 

Let’s pause and decode what this section means! 

18015G25KT

The first three numbers show us which direction the wind is coming from.

“180” means the wind is coming from 180 degrees (south)

If the wind is variable (wind that changes its direction frequently), it starts with “VRB.”

The next two numbers show the wind speed in knots. If the wind is lethally strong (over 99 knots), then it's shown three numbers.

“15” means the wind speed is 15 knots (that’s about 17 MPH!)

So here, the wind is coming from 180 degrees at 15 knots.

“G25KT” means wind gusts up to 25 knots (that’s about 28 MPH!)

You don’t always see wind gusts, but if you do, it starts with a G.

And anytime you see KT (knots), just know it’s about the wind! 

Visibility

This is the visibility. It’s shown in Statute Miles.

‘10 SM’ means there are 10 statute miles of visibility ahead!

The bigger this number is, the farther you’ll be able to see.

Remember, you need 3 SM of visibility to even conduct a drone mission!

Precipitation

This is the precipitation (rain).

Here, DZ means “moderate drizzle.”

In these weather reports, there are a lot of 2-letter codes that are used to describe precipitation and weather.

It’s important to know what the weather’s going to be like. You definitely don’t want to fly in a thunderstorm!

Now, let’s move onto clouds.

Cloud Cover

The cloud cover section in a METAR report describes how much of the sky is covered by clouds and at what altitude (how high) they are.

So it shows pilots the amount of clouds in the sky and their height near an airport.

Each type of cloud gets its own short part in the report.

The three letters show how much of the sky is covered by clouds, and the numbers tell us the cloud base (where the clouds start) in thousands of feet AGL.

If you see these numbers start with 'OVC', it means it’s overcast, so the entire sky is covered in clouds! 

METAR KJFK 121651Z 18015G25KT 10SM SCT020 BKN250 30/20 A3005 RMK AO2 SLP177

We don’t see it here, but you probably might see it on another METAR report! 

Anyways, let’s get back to what we see above us. 

Let’s pause to decode it! 

SCT020

Cloud Cover

This means there are Scattered Clouds at 2,000 feet (AGL).

(Just like MEFs, we add two zeros!)

BKN250

Cloud Cover

This means there are Broken Clouds at 25,000 feet (AGL). Still add two zeros!

So there are Scattered Clouds starting at 2,000 Feet AGL, and Broken Clouds starting at 25,000 Feet AGL. 

To get those numbers, we take the number after the 0 and add two zeroes (00) to it. They’re always measured in AGL. 

It’s important to know what the clouds are like – you should always avoid flying in clouds!

Temperature and Dew Point 

This is the temperature and the dew point near the airport. 

The first number is the temperature of the air, measured Celsius (we use Fahrenheit). Here, it’s 30 degrees Celsius.

The second number is the dew point, also measured  Celsius. Here, it’s 20 degrees Celsius.

If it’s below freezing, it will start with an “M” for “minus”.

Altimeter Setting

A stands for Altimeter. 

An Altimeter is a cool instrument that tells airplane pilots how far away they are from the ground by showing them the current atmospheric pressure! 

Pilots need to adjust their altimeters so they can know their exact altitude while flying.

This is the number that an airplane pilot should set their altimeter to: 30.05 Hg. 

Remarks (Notes)

This section just includes any additional information.

Let’s pause and decode it! 

Remarks

RMK

This means ‘Remark’

A02

This is a code that provides additional information about the weather from an automated source.

“AO2” means the station has an
automated precipitation sensor.

“AO2” means that the weather station is automated and can detect and report rain or snow. 

If you see AO1, there’s an automated station without a precipitation (rain or snow) sensor. 

ACTIVITY 

If you could redesign a METAR Report to be less confusing, how would you do it? 

For me, it would be the date and time! I’m American.  

Great work! I see you’re all a few steps closer to becoming a certified drone pilot.